Method and apparatus of handling time gap for sidelink hybrid automatic request (HARQ) in network scheduling mode in a wireless communication system

ABSTRACT

A method and apparatus are disclosed from the perspective of a device to perform sidelink communication. In one embodiment, the method includes the device receiving a sidelink grant from a network node, wherein the sidelink grant schedules or assigns multiple sidelink resources. The method further includes the device generating a data packet comprising or multiplexing sidelink data from Sidelink (SL) logical channel(s) with SL Hybrid Automatic Request (HARD) feedback enabled. The method further includes the device performing two sidelink transmissions for the data packet on two adjacent, neighbor, or consecutive sidelink resources among the multiple sidelink resources if a time gap of the two adjacent, neighbor, or consecutive sidelink resources is larger than or equal to a minimum time gap.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present Application claims the benefit of U.S. Provisional PatentApplication Ser. No. 63/007,638 filed on Apr. 9, 2020 and U.S.Provisional Patent Application Ser. No. 63/035,354 filed on Jun. 5,2020, the entire disclosures of which are incorporated herein in theirentirety by reference.

FIELD

This disclosure generally relates to wireless communication networks,and more particularly, to a method and apparatus handling time gap forsidelink Hybrid Automatic Request (HARQ) in network scheduling mode in awireless communication system.

BACKGROUND

With the rapid rise in demand for communication of large amounts of datato and from mobile communication devices, traditional mobile voicecommunication networks are evolving into networks that communicate withInternet Protocol (IP) data packets. Such IP data packet communicationcan provide users of mobile communication devices with voice over IP,multimedia, multicast and on-demand communication services.

An exemplary network structure is an Evolved Universal Terrestrial RadioAccess Network (E-UTRAN). The E-UTRAN system can provide high datathroughput in order to realize the above-noted voice over IP andmultimedia services. A new radio technology for the next generation(e.g., 5G) is currently being discussed by the 3GPP standardsorganization. Accordingly, changes to the current body of 3GPP standardare currently being submitted and considered to evolve and finalize the3GPP standard.

SUMMARY

A method and apparatus are disclosed from the perspective of a device toperform sidelink communication. In one embodiment, the method includesthe device receiving a sidelink grant from a network node, wherein thesidelink grant schedules or assigns multiple sidelink resources. Themethod further includes the device generating a data packet comprisingor multiplexing sidelink data from Sidelink (SL) logical channel(s) withSL Hybrid Automatic Request (HARQ) feedback enabled. The method furtherincludes the device performing two sidelink transmissions for the datapacket on two adjacent, neighbor, or consecutive sidelink resourcesamong the multiple sidelink resources if a time gap of the two adjacent,neighbor, or consecutive sidelink resources is larger than or equal to aminimum time gap. In addition, the method includes the device beingallowed to drop, skip, or cancel a sidelink transmission on one sidelinkresource of the two adjacent, neighbor, or consecutive sidelinkresources among the multiple sidelink resources if the time gap of thetwo adjacent, neighbor, or consecutive sidelink resources is less than aminimum time gap.

Furthermore, an alternative method and apparatus are disclosed from theperspective of a device to perform sidelink communication. In oneembodiment, the method includes the device receiving a sidelink grantfrom a network node, wherein the sidelink grant schedules or assignsmultiple sidelink resources. The method further includes the devicegenerating a data packet comprising or multiplexing sidelink data fromone or more Sidelink (SL) logical channel(s), wherein the one or more SLlogical channel(s) is determined or selected at least based on time gapof any two adjacent sidelink resources among the multiple sidelinkresources. In addition, the method includes the device performing one ormore sidelink transmission(s) on one or more of the multiple sidelinkresources, wherein the one or more sidelink transmission(s) delivers orcomprises the data packet.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a diagram of a wireless communication system according toone exemplary embodiment.

FIG. 2 is a block diagram of a transmitter system (also known as accessnetwork) and a receiver system (also known as user equipment or UE)according to one exemplary embodiment.

FIG. 3 is a functional block diagram of a communication system accordingto one exemplary embodiment.

FIG. 4 is a functional block diagram of the program code of FIG. 3according to one exemplary embodiment.

FIG. 5 is a reproduction of Table 4.3-1 of 3GPP TS 38.212 V16.1.0.

FIG. 6 is a reproduction of Table 4.3-2 of 3GPP TS 38.212 V16.1.0.

FIG. 7 is a reproduction of Table 7.3.1-1 of 3GPP TS 38.212 V16.1.0.

FIG. 8 is a diagram according to one exemplary embodiment.

FIG. 9 is a diagram according to one exemplary embodiment.

FIG. 10 is a flow chart according to one exemplary embodiment.

FIG. 11 is a flow chart according to one exemplary embodiment.

DETAILED DESCRIPTION

The exemplary wireless communication systems and devices described belowemploy a wireless communication system, supporting a broadcast service.Wireless communication systems are widely deployed to provide varioustypes of communication such as voice, data, and so on. These systems maybe based on code division multiple access (CDMA), time division multipleaccess (TDMA), orthogonal frequency division multiple access (OFDMA),3GPP LTE (Long Term Evolution) wireless access, 3GPP LTE-A orLTE-Advanced (Long Term Evolution Advanced), 3GPP2 UMB (Ultra MobileBroadband), WiMax, 3GPP NR (New Radio), or some other modulationtechniques.

In particular, the exemplary wireless communication systems devicesdescribed below may be designed to support one or more standards such asthe standard offered by a consortium named “3rd Generation PartnershipProject” referred to herein as 3GPP, including: TS 38.211 V16.1.0(2020-03), “NR; Physical channels and modulation (Release 16)”; TS38.212 V16.1.0 (2020-03), “NR; Multiplexing and channel coding (Release16)”; TS 38.213 V16.1.0 (2020-03), “NR; Physical layer procedures forcontrol (Release 16)”; TS 38.214 V16.1.0 (2020-03), “NR; Physical layerprocedures for data (Release 16)”; TS 38.321 V16.0.0 (2020-03), “NR;Medium Access Control (MAC) protocol specification (Release 16)”;R1-1810051, “Final Report of 3GPP TSG RAN WG1 #94 V1.0.0 (Gothenburg,Sweden, 20-24 Aug. 2018)”; R1-1905921, “Final Report of 3GPP TSG RAN WG1#96bis V1.0.0 (Xi'an, China, 8-12 Apr. 2019)”; R1-1907973, “Final Reportof 3GPP TSG RAN WG1 #97 V1.0.0 (Reno, USA, 13-17 May 2019)”; R1-1909942,“Final Report of 3GPP TSG RAN WG1 #98 V1.0.0 (Prague, Czech Rep., 26-30Aug. 2019)”; Draft Report of 3GPP TSG RAN WG1 #99 V1.0.0 (Reno, USA,18-22 Nov. 2019); and Draft Report of 3GPP TSG RAN WG1 #100-e V0.2.0(Online meeting, 18 Feb.-6 Mar. 2020). The standards and documentslisted above are hereby expressly incorporated by reference in theirentirety.

FIG. 1 shows a multiple access wireless communication system accordingto one embodiment of the invention. An access network 100 (AN) includesmultiple antenna groups, one including 104 and 106, another including108 and 110, and an additional including 112 and 114. In FIG. 1, onlytwo antennas are shown for each antenna group, however, more or fewerantennas may be utilized for each antenna group. Access terminal 116(AT) is in communication with antennas 112 and 114, where antennas 112and 114 transmit information to access terminal 116 over forward link120 and receive information from access terminal 116 over reverse link118. Access terminal (AT) 122 is in communication with antennas 106 and108, where antennas 106 and 108 transmit information to access terminal(AT) 122 over forward link 126 and receive information from accessterminal (AT) 122 over reverse link 124. In a FDD system, communicationlinks 118, 120, 124 and 126 may use different frequency forcommunication. For example, forward link 120 may use a differentfrequency then that used by reverse link 118.

Each group of antennas and/or the area in which they are designed tocommunicate is often referred to as a sector of the access network. Inthe embodiment, antenna groups each are designed to communicate toaccess terminals in a sector of the areas covered by access network 100.

In communication over forward links 120 and 126, the transmittingantennas of access network 100 may utilize beamforming in order toimprove the signal-to-noise ratio of forward links for the differentaccess terminals 116 and 122. Also, an access network using beamformingto transmit to access terminals scattered randomly through its coveragecauses less interference to access terminals in neighboring cells thanan access network transmitting through a single antenna to all itsaccess terminals.

An access network (AN) may be a fixed station or base station used forcommunicating with the terminals and may also be referred to as anaccess point, a Node B, a base station, an enhanced base station, anevolved Node B (eNB), or some other terminology. An access terminal (AT)may also be called user equipment (UE), a wireless communication device,terminal, access terminal or some other terminology.

FIG. 2 is a simplified block diagram of an embodiment of a transmittersystem 210 (also known as the access network) and a receiver system 250(also known as access terminal (AT) or user equipment (UE)) in a MIMOsystem 200. At the transmitter system 210, traffic data for a number ofdata streams is provided from a data source 212 to a transmit (TX) dataprocessor 214.

In one embodiment, each data stream is transmitted over a respectivetransmit antenna. TX data processor 214 formats, codes, and interleavesthe traffic data for each data stream based on a particular codingscheme selected for that data stream to provide coded data.

The coded data for each data stream may be multiplexed with pilot datausing OFDM techniques. The pilot data is typically a known data patternthat is processed in a known manner and may be used at the receiversystem to estimate the channel response. The multiplexed pilot and codeddata for each data stream is then modulated (i.e., symbol mapped) basedon a particular modulation scheme (e.g., BPSK, QPSK, M-PSK, or M-QAM)selected for that data stream to provide modulation symbols. The datarate, coding, and modulation for each data stream may be determined byinstructions performed by processor 230.

The modulation symbols for all data streams are then provided to a TXMIMO processor 220, which may further process the modulation symbols(e.g., for OFDM). TX MIMO processor 220 then provides N_(T) modulationsymbol streams to N_(T) transmitters (TMTR) 222 a through 222 t. Incertain embodiments, TX MIMO processor 220 applies beamforming weightsto the symbols of the data streams and to the antenna from which thesymbol is being transmitted.

Each transmitter 222 receives and processes a respective symbol streamto provide one or more analog signals, and further conditions (e.g.,amplifies, filters, and upconverts) the analog signals to provide amodulated signal suitable for transmission over the MIMO channel. N_(T)modulated signals from transmitters 222 a through 222 t are thentransmitted from N_(T) antennas 224 a through 224 t, respectively.

At receiver system 250, the transmitted modulated signals are receivedby N_(R) antennas 252 a through 252 r and the received signal from eachantenna 252 is provided to a respective receiver (RCVR) 254 a through254 r. Each receiver 254 conditions (e.g., filters, amplifies, anddownconverts) a respective received signal, digitizes the conditionedsignal to provide samples, and further processes the samples to providea corresponding “received” symbol stream.

An RX data processor 260 then receives and processes the N_(R) receivedsymbol streams from N_(R) receivers 254 based on a particular receiverprocessing technique to provide N_(T) “detected” symbol streams. The RXdata processor 260 then demodulates, deinterleaves, and decodes eachdetected symbol stream to recover the traffic data for the data stream.The processing by RX data processor 260 is complementary to thatperformed by TX MIMO processor 220 and TX data processor 214 attransmitter system 210.

A processor 270 periodically determines which pre-coding matrix to use(discussed below). Processor 270 formulates a reverse link messagecomprising a matrix index portion and a rank value portion.

The reverse link message may comprise various types of informationregarding the communication link and/or the received data stream. Thereverse link message is then processed by a TX data processor 238, whichalso receives traffic data for a number of data streams from a datasource 236, modulated by a modulator 280, conditioned by transmitters254 a through 254 r, and transmitted back to transmitter system 210.

At transmitter system 210, the modulated signals from receiver system250 are received by antennas 224, conditioned by receivers 222,demodulated by a demodulator 240, and processed by a RX data processor242 to extract the reserve link message transmitted by the receiversystem 250. Processor 230 then determines which pre-coding matrix to usefor determining the beamforming weights then processes the extractedmessage.

Turning to FIG. 3, this figure shows an alternative simplifiedfunctional block diagram of a communication device according to oneembodiment of the invention. As shown in FIG. 3, the communicationdevice 300 in a wireless communication system can be utilized forrealizing the UEs (or ATs) 116 and 122 in FIG. 1 or the base station (orAN) 100 in FIG. 1, and the wireless communications system is preferablythe NR system. The communication device 300 may include an input device302, an output device 304, a control circuit 306, a central processingunit (CPU) 308, a memory 310, a program code 312, and a transceiver 314.The control circuit 306 executes the program code 312 in the memory 310through the CPU 308, thereby controlling an operation of thecommunications device 300. The communications device 300 can receivesignals input by a user through the input device 302, such as a keyboardor keypad, and can output images and sounds through the output device304, such as a monitor or speakers. The transceiver 314 is used toreceive and transmit wireless signals, delivering received signals tothe control circuit 306, and outputting signals generated by the controlcircuit 306 wirelessly. The communication device 300 in a wirelesscommunication system can also be utilized for realizing the AN 100 inFIG. 1.

FIG. 4 is a simplified block diagram of the program code 312 shown inFIG. 3 in accordance with one embodiment of the invention. In thisembodiment, the program code 312 includes an application layer 400, aLayer 3 portion 402, and a Layer 2 portion 404, and is coupled to aLayer 1 portion 406. The Layer 3 portion 402 generally performs radioresource control. The Layer 2 portion 404 generally performs linkcontrol. The Layer 1 portion 406 generally performs physicalconnections.

3GPP TS 38.211 V16.1.0 specifies generation for physical sidelink sharedchannel, physical sidelink control channel, and physical sidelinkfeedback channel in NR, as discussed below. In general, the physicalsidelink shared channel, the physical sidelink control channel, and thephysical sidelink feedback channel are for communication betweendevices, i.e. PC5 link or device-to-device link. The physical sidelinkshared channel (PSSCH) delivers data/transport block for sidelink sharedchannel (SL-SCH). The physical sidelink control channel (PSCCH) deliverssidelink control information (SCI). The physical sidelink feedbackchannel (PSFCH) delivers sidelink HARQ-ACK.

8 Sidelink

8.1 Overview

8.1.1 Overview of Physical Channels

A sidelink physical channel corresponds to a set of resource elementscarrying information originating from higher layers. The followingsidelink physical channels are defined:

-   -   Physical Sidelink Shared Channel, PSSCH    -   Physical Sidelink Broadcast Channel, PSBCH    -   Physical Sidelink Control Channel, PSCCH    -   Physical Sidelink Feedback Channel, PSFCH

3GPP TS 38.212 V16.1.0 specifies downlink control information forscheduling of sidelink and sidelink control information in NR, asdiscussed below. The downlink control information is for communicationbetween network node and UE, i.e. Uu link. The sidelink controlinformation are for communication between UEs, i.e. PC5 link orsidelink.

4.3 Sidelink

Table 4.3-1 specifies the mapping of the sidelink transport channels totheir corresponding physical channels. Table 4.3-2 specifies the mappingof the sidelink control information and sidelink feedback controlinformation to their corresponding physical channels.

[Table 4.3-1 of 3GPP TS 38.212 V16.1.0 is reproduced as FIG. 5]

[Table 4.3-2 of 3GPP TS 38.212 V16.1.0 is reproduced as FIG. 6]

<Unchanged parts are omitted>

7.3.1 DCI Formats

The DCI formats defined in table 7.3.1-1 are supported.

[Table 7.3.1-1 of 3GPP TS 38.212 V16.1.0, entitled “DCI formats”, isreproduced as FIG. 7]

<Unchanged parts are omitted>

7.3.1.4 DCI formats for scheduling of sidelink

7.3.1.4.1 Format 3_0

DCI format 3_0 is used for scheduling of NR PSCCH and NR PSSCH in onecell.

The following information is transmitted by means of the DCI format 3_0with CRC scrambled by SL-RNTI or SL-CS-RNTI:

-   -   Time gap—[x] bits determined by higher layer parameter        sl-DCI-ToSL-Trans, as defined in clause x.x.x of [6, TS 38.214]    -   HARQ process ID—[x] bits as defined in clause 16.4 of [5, TS        38.213]

New data indicator—1 bit as defined in clause 16.4 of [5, TS 38.213]

-   -   Lowest index of the subchannel allocation to the initial        transmission—┌log₂(N_(Channel) ^(SL))┐ bits as defined in clause        x.x.x of [6, TS 38.214]    -   SCI format 0-1 fields according to clause 8.3.1.1:    -   Frequency resource assignment.    -   Time resource assignment.    -   PSFCH-to-HARQ feedback timing indicator—3 bits as defined in        clause x.x.x of [6, TS 38.214].    -   PUCCH resource indicator—3 bits as defined in clause x.x.x of        [6, TS 38.214].    -   Configuration index—0 bit if the UE is not configured to monitor        DCI format 3_0 with CRC scrambled by SL-CS-RNTI; otherwise [x]        bits as defined in clause x.x.x of [6, TS 38.214]. If the UE is        configured to monitor DCI format 3_0 with CRC scrambled by        SL-CS-RNTI, this field is reserved for DCI format 3_0 with CRC        scrambled by SL-RNTI.

<Unchanged parts are omitted>

8.3 Sidelink Control Information on PSCCH

SCI carried on PSCCH is a 1^(st)-stage SCI, which transports sidelinkscheduling information.

8.3.1 1^(st)-Stage SCI Formats

[ . . . ]

8.3.1.1 SCI format 0-1

SCI format 0-1 is used for the scheduling of PSSCH and 2^(nd)-stage-SCIon PSSCH

The following information is transmitted by means of the SCI format 0-1:

-   -   Priority—3 bits as defined in clause x.x.x of [6, TS 38.214].    -   Frequency resource assignment

$- \left\lceil {\log_{2}\left( \frac{N_{subChannel}^{SL}\left( {N_{subChannel}^{SL} + 1} \right)}{2} \right)} \right\rceil$bits when the value of the higher layer parameter sl-MaxNumPerReserve isconfigured to 2; otherwise

$\left\lceil {\log_{2}\left( \frac{{N_{subChannel}^{SL}\left( {N_{subChannel}^{SL} + 1} \right)}\left( {{2N_{subChannel}^{SL}} + 1} \right)}{6} \right)} \right\rceil$bits when the value of the higher layer parameter sl-MaxNumPerReserve isconfigured to 3, as defined in clause x.x.x of [6, TS 38.214].

-   -   Time resource assignment—5 bits when the value of the higher        layer parameter sl-MaxNumPerReserve is configured to 2;        otherwise 9 bits when the value of the higher layer parameter        sl-MaxNumPerReserve is configured to 3, as defined in clause        x.x.x of [6, TS 38.214].    -   Resource reservation period—┌log₂(N_(reservPeriod))┐ bits as        defined in clause x.x.x of [6, TS 38.214], if higher parameter        sl-MultiReserveResource is configured; 0 bit otherwise.    -   DMRS pattern—[x] bits as defined in clause 8.4.1.1.2 of [4, TS        38.211], if more than one DMRS patterns are configured by higher        layer parameter sl-PSSCH-DMRS-TimePattern; 0 bit otherwise.    -   2^(nd)-stage SCI format—[x] bits as defined in clause x.x.x of        [6, TS 38.214].    -   Beta_offset indicator—[2] bits as provided by higher layer        parameter sl-BetaOffsets2ndSCI.    -   Number of DMRS port—1 bit as defined in Table 8.3.1.1-1.    -   Modulation and coding scheme—5 bits as defined in clause 8.1.3        of [6, TS 38.214].    -   Reserved—[2-4] bits as determined by higher layer parameter        sl-NumReservedBits, with value set to zero.

8.4 Sidelink Control Information on PSSCH

SCI carried on PSSCH is a 2^(nd)-stage SCI, which transports sidelinkscheduling information.

8.4.1 2^(nd)-Stage SCI Formats

[ . . . ]

8.4.1.1 SCI Format 0-2

SCI format 0-2 is used for the decoding of PSSCH.

The following information is transmitted by means of the SCI format 0-2:

-   -   HARQ Process ID—[x] bits as defined in clause 16.4 of [5, TS        38.213].    -   New data indicator—1 bit as defined in clause 16.4 of [5, TS        38.213].    -   Redundancy version—2 bits as defined in clause x.x.x of [6, TS        38.214].    -   Source ID—8 bits as defined in clause x.x.x of [6, TS 38.214].    -   Destination ID—16 bits as defined in clause x.x.x of [6, TS        38.214].    -   CSI request—1 bit as defined in clause 8.2.1 of [6, TS 38.214].

If the 2^(nd)-stage SCI format field in the corresponding SCI format 0-1indicates type 1 groupcast as defined in clause x.x.x of [6, TS 38.214],the following fields are present:

-   -   Zone ID—12 bits as defined in clause x.x.x of [9, TS 38.331].    -   Communication range requirement—4 bits as defined in clause        x.x.x of [9, TS 38.331]

[ . . . ]

8.4.5 Multiplexing of Coded 2^(nd)-Stage SCI Bits to PSSCH

The coded 2^(nd)-stage SCI bits are multiplexed onto PSSCH according tothe procedures in Clause 8.2.1.

3GPP TS 38.213 V16.1.0 specifies the UE procedure for reporting HARQ-ACKon sidelink and reporting HARQ-ACK on PUCCH in NR.

16 UE Procedures for Sidelink

A UE is provided by locationAndBandwidth-SL a BWP for SL transmissions(SL BWP) with numerology and resource grid determined as described in[4, TS38.211]. For a resource pool within the SL BWP, the UE is providedby numSubchannel a number of sub-channels where each sub-channelincludes a number of contiguous RBs provided by subchannelsize. Thefirst RB of the first sub-channel in the SL BWP is indicated bystartRB-Subchannel. Available slots for a resource pool are provided bytimeresourcepool and occur with a periodicity provided by‘periodResourcePool’. For an available slot without S-SS/PSBCH blocks,SL transmissions can start from a first symbol indicated bystartSLsymbols and be within a number of consecutive symbols indicatedby lengthSLsymbols. For an available slot with S-SS/PSBCH blocks, thefirst symbol and the number of consecutive symbols is predetermined.

The UE expects to use a same numerology in the SL BWP and in an activeUL BWP in a same carrier of a same cell. If the active UL BWP numerologyis different than the SL BWP numerology, the SL BWP is deactivated.

A UE transmitting using a Mode-1 grant uses the corresponding fields inSCI to reserve the next resource(s) allocated by the same grant.

[ . . . ]

16.3 UE Procedure for Reporting HARQ-ACK on Sidelink

A UE can be indicated by an SCI format scheduling a PSSCH reception, inone or more sub-channels from a number of N_(subch) ^(PSSCH)sub-channels, to transmit a PSFCH with HARQ-ACK information in responseto the PSSCH reception. The UE provides HARQ-ACK information thatincludes ACK or NACK, or only NACK.

A UE can be provided, by periodPSFCHresource, a number of slots in aresource pool for a period of PSFCH transmission occasion resources. Ifthe number is zero, PSFCH transmissions from the UE in the resource poolare disabled.

A UE may be indicated by higher layers to not transmit a PSFCH inresponse to a PSSCH reception [11, TS 38.321].

If a UE receives a PSSCH in a resource pool and a ZYX field in a SCIformat 0_2 scheduling the PSSCH reception indicates to the UE to reportHARQ-ACK information for the PSSCH reception [5, TS 38.212], the UEprovides the HARQ-ACK information in a PSFCH transmission in theresource pool. The UE transmits the PSFCH in a first slot that includesPSFCH resources and is at least a number of slots, provided byMinTimeGapPSFCH, of the resource pool after a last slot of the PSSCHreception.

A UE is provided by rbSetPSFCH a set of M_(PRB,set) ^(PSFCH) PRBs in aresource pool for PSFCH transmission in a PRB of the resource pool. Fora number of N_(subch) sub-channels for the resource pool, provided bynumSubchannel, and a number of N_(PSSCH) ^(PSFCH) PSSCH slots associatedwith a PSFCH slot, provided by periodPSFCHresource, the UE allocates the[(i+j·N_(PSSCH) ^(PSFCH))·M_(subch,slot) ^(PSFCH),(i+1+j·N_(PSSCH)^(PSFCH))·M_(subch,slot) ^(PSFCH)−1] PRBs from the M_(PRB,set) ^(PSFCH)PRBs to slot i and sub channel j, where M_(subch,slot)^(PSFCH)=M_(PRB,set) ^(PSFCH)/(N_(subch)·N_(PSSCH)^(PSFCH)),0≤i<N_(PSSCH) ^(PSFCH),0≤j<N_(subch), and the allocationstarts in an ascending order of i and continues in an ascending order ofj. The UE expects that M_(PRB,set) ^(PSFCH) is a multiple ofN_(subch)·N_(PSSCH) ^(PSFCH).

A UE determines a number of PSFCH resources available for multiplexingHARQ-ACK information in a PSFCH transmission as R_(PRB,CS)^(PSFCH)=N_(type) ^(PSFCH)·M_(subch,slot) ^(PSFCH)·N_(CS) ^(PSFCH) whereN_(CS) ^(PSFCH) is a number of cyclic shift pairs for the resource pooland, based on an indication by higher layers,

-   -   N_(type) ^(PSFCH)=1 and the M_(subch,slot) ^(PSFCH) PRBs are        associated with the starting sub-channel of the corresponding        PSSCH    -   N_(type) ^(PSFCH)=N_(subch) ^(PSFCH) and the N_(subch)        ^(PSSCH)·M_(subch,slot) ^(PSFCH) PRBs are associated with one or        more sub-channels from the N_(subch) ^(PSSCH) sub-channels of        the corresponding PSSCH

The PSFCH resources are first indexed according to an ascending order ofthe PRB index, from the N_(type) ^(PSFCH)·M_(subch,slot) ^(PSFCH) PRBs,and then according to an ascending order of the cyclic shift pair indexfrom the N_(CS) ^(PSFCH) cyclic shift pairs.

A UE determines an index of a PSFCH resource for a PSFCH transmission inresponse to a PSSCH reception, as (P_(ID)+M_(ID))mod R_(PRB,CS) ^(PSFCH)where P_(ID) is a physical layer source ID provided by SCI format 0_2[5, TS 38.212] scheduling the PSSCH reception, M_(ID) is zero or M_(ID)is the identity of the UE receiving the PSSCH as indicated by higherlayers.

16.4 UE Procedure for Transmitting PSCCH

A UE can be provided a number of symbols in a resource pool, bytimeResourcePSCCH, starting from a second symbol that is available forSL transmissions in a slot, and a number of PRBs in the resource pool,by frequencyResourcePSCCH, for a PSCCH transmission with a SCI format0_1.

A UE that transmits a PSCCH with SCI format 0_1 using sidelink resourceallocation mode 1 [6, TS38.214]

-   -   sets a value of a HARQ process ID field as indicated by higher        layers    -   for an initial transmission of a TB that is scheduled by a DCI        format 3_0 with CRC scrambled by SL-RNTI, the UE    -   toggles the NDI field value in SCI format 0_1, if the NDI field        value in DCI format 3_0 is toggled    -   does not toggle the NDI field value in SCI format 0_1, if the        NDI field value in DCI format 3_0 is not toggled    -   for subsequent transmissions of the TB that are scheduled by the        DCI format 3_0 with CRC scrambled by SL-RNTI, the UE does not        toggle the NDI field value in SCI format 0_1.

3GPP TS 38.214 V16.1.0 specifies the UE procedure for sidelink sharedchannel in NR, as discussed below. Sidelink resource allocation mode 1or sidelink resource allocation mode 2 is utilized for acquiringsidelink resource(s) for sidelink shared channel.

8 Physical Sidelink Shared Channel Related Procedures

A UE can be configured by higher layers with one or more sidelinkresource pools. A sidelink resource pool can be for transmission ofPSSCH, as described in Clause 8.1, or for reception of PSSCH, asdescribed in Clause 8.3 and can be associated with either sidelinkresource allocation mode 1 or sidelink resource allocation mode 2.

In the frequency domain, a sidelink resource pool consists ofnumSubchannel contiguous sub-channels. A sub-channel consists ofsubchannelsize contiguous PRBs, where numSubchannel and subchannelsizeare higher layer parameters.

8.1 UE Procedure for Transmitting the Physical Sidelink Shared Channel

Each PSSCH transmission is associated with an PSCCH transmission.

That PSCCH transmission carries the 1^(st) stage of the SCI associatedwith the PSSCH transmission; the 2^(nd) stage of the associated SCI iscarried within the resource of the PSSCH.

If the UE transmits SCI format 0-1 on PSCCH according to a PSCCHresource configuration in slot n and PSCCH resource m, then for theassociated PSSCH transmission in the same slot

-   -   one transport block is transmitted with up to two layers;    -   The number of layers (u) is determined according to the “Number        of DMRS port” field in the SCI    -   The set of consecutive symbols within the slot for transmission        of the PSSCH is determined according to clause 8.1.2.1;    -   The set of contiguous resource blocks for transmission of the        PSSCH is determined according to clause 8.1.2.2;

[ . . . ]

8.1.2 Resource Allocation

In sidelink resource allocation mode 1:

-   -   for PSSCH and PSCCH transmission, dynamic grant, configured        grant type 1 and configured grant type 2 are supported.

8.1.2.1 Resource Allocation in Time Domain

The UE shall transmit the PSSCH in the same slot as the associatedPSCCH.

The minimum resource allocation unit in the time domain is a slot.

The UE shall transmit the PSSCH in consecutive symbols within the slot,subject to the following restrictions:

-   -   The UE shall not transmit PSSCH in symbols which are not        configured for sidelink. A symbol is configured for sidelink,        according to higher layer parameters startSLsymbols and        lengthSLsymbols, where startSLsymbols is the symbol index of the        first symbol of lengthSLsymbols consecutive symbols configured        for sidelink.    -   Within the slot, PSSCH resource allocation starts at symbol        startSLsymbols+1.    -   The UE shall not transmit PSSCH in symbols which are configured        for use by PSFCH, if PSFCH is configured in this slot.    -   The UE shall not transmit PSSCH in the last symbol configured        for sidelink.    -   The UE shall not transmit PSSCH in the symbol immediately        preceding the symbols which are configured for use by PSFCH, if        PSFCH is configured in this slot.

In sidelink resource allocation mode 1:

-   -   For sidelink dynamic grant, the PSSCH transmission is scheduled        by a DCI format 3_0.    -   For sidelink configured grant type 2, the configured grant is        activated by a DCI format 3_0.    -   For sidelink dynamic grant and sidelink configured grant type 2:        -   The “Time gap” field value m of the DCI format 3_0 provides            an index m+1 into a slot offset table. That table is given            by higher layer parameter timeGapFirstSidelinkTransmission            and the table value at index m+1 will be referred to as slot            offset K_(SL).        -   The slot of the first sidelink transmission scheduled by the            DCI is the first SL slot of the corresponding resource pool            that starts not earlier than T_(DL)−T_(TA)/2+K_(SL)×T_(slot)            where T_(DL) is starting time of the downlink slot carrying            the corresponding DCI, T_(TA) is the timing advance value            and K_(SL) is the slot offset between the slot DCI and the            first sidelink transmission scheduled by DCI, T_(c) is as            defined in 38.211, and T_(slott) is the SL slot duration.        -   For sidelink configured grant type 1:            -   The slot of the first sidelink transmissions follows the                higher layer configuration according to [10, TS 38.321].

8.1.2.2 Resource Allocation in Frequency Domain

The resource allocation unit in the frequency domain is the sub-channel.

The sub-channel assignment for sidelink transmission is determined usingthe “Frequency resource assignment” field in the associated SCI.

The lowest sub-channel for sidelink transmission is the sub-channel onwhich the lowest PRB of the associated PSCCH is transmitted.

If a PSSCH scheduled by a PSCCH would overlap with resources containingthe PSCCH, the resources corresponding to a union of the PSCCH thatscheduled the PSSCH and associated PSCCH DM-RS are not available for thePSSCH.

[ . . . ]

8.1.4 UE Procedure for Determining the Subset of Resources to beReported to Higher Layers in PSSCH Resource Selection in SidelinkResource Allocation Mode 2

In resource allocation mode 2, the higher layer can request the UE todetermine a subset of resources from which the higher layer will selectresources for PSSCH/PSCCH transmission. To trigger this procedure, inslot n, the higher layer provides the following parameters for thisPSSCH/PSCCH transmission:

-   -   the resource pool from which the resources are to be reported;    -   L1 priority, prio_(TX);    -   the remaining packet delay budget;    -   the number of sub-channels to be used for the PSSCH/PSCCH        transmission in a slot, L_(subCH);    -   optionally, the resource reservation interval, P_(rsvp_TX), in        units of ms.

The following higher layer parameters affect this procedure:

-   -   t2min_SelectionWindow: internal parameter T_(2min) is set to the        corresponding value from higher layer parameter        t2min_SelectionWindow for the given value of prio_(TX).    -   SL-ThresRSRP_pi_pj: this higher layer parameter provides an RSRP        threshold for each combination (p_(i), p_(j)), where p_(i) is        the value of the priority field in a received SCI format 0-1 and        p_(j) is the priority of the transmission of the UE selecting        resources; for a given invocation of this procedure,        p_(j)=prio_(TX)    -   RSforSensing selects if the UE uses the PSSCH-RSRP or PSCCH-RSRP        measurement, as defined in clause 8.4.2.1.    -   reservationPeriodAllowed    -   t0_SensingWindow: internal parameter T₀ is defined as the number        of slots corresponding to t0_SensingWindow ms.

The resource reservation interval, P_(rsvp_TX), if provided, isconverted from units of ms to units of logical slots, resulting inP_(rsvp_TX)′

Notation:

(t₀ ^(SL),t₁ ^(SL),t₂ ^(SL), . . . ) denotes the set of slots which canbelong to a sidelink resource pool and is defined in [TBD].

The following steps are used:

1) A candidate single-slot resource for transmission R_(x,y) is definedas a set of L_(subCH) contiguous sub-channels with sub-channel x+j inslot t_(y) ^(SL) where j=0, . . . , L_(subCH)−1. The UE shall assumethat any set of L_(subCH) contiguous sub-channels included in thecorresponding resource pool within the time interval [n+T₁,n+T₂]correspond to one candidate single-slot resource, where

-   -   selection of T₁ is up to UE implementation under        0≤T₁≤T_(proc,1), where T_(proc,1) is TBD;

if T_(2min) is shorter than the remaining packet delay budget (in slots)then T₂ is up to UE implementation subject to T_(2min)≤T₂≤remainingpacket budget (in slots); otherwise T₂ is set to the remaining packetdelay budget (in slots).

The total number of candidate single-slot resources is denoted byM_(total)

2) The sensing window is defined by the range of slots[n−T₀,n−T_(proc,0)) where T₀ is defined above and T_(proc,1) is TBD. TheUE shall monitor slots which can belong to a sidelink resource poolwithin the sensing window except for those in which its owntransmissions occur. The UE shall perform the behaviour in the followingsteps based on PSCCH decoded and RSRP measured in these slots.

3) The internal parameter Th(p_(i)) is set to the corresponding valuefrom higher layer parameter SL-ThresRSRP_pi_pj for p_(j) equal to thegiven value of prio_(TX) and each priority value p_(i)

4) The set S_(A) is initialized to the set of all the candidatesingle-slot resources.

5) The UE shall exclude any candidate single-slot resource from the setS_(A) if it meets all the following conditions:

-   -   the UE has not monitored slot t_(m) ^(SL) in Step 2.    -   for any periodicity value allowed by the higher layer parameter        reservationPeriodAllowed and a hypothetical SCI format 0-1        received in slot t_(m) ^(SL) with “Resource reservation period”        field set to that periodicity value and indicating all        subchannels of the resource pool in this slot, condition c in        step 6 would be met.

6) The UE shall exclude any candidate single-slot resource R_(x,y) fromthe set S_(A) if it meets all the following conditions:

-   -   a) the UE receives an SCI format 0-1 in slot t_(m) ^(SL), and        “Resource reservation period” field, if present, and “Priority”        field in the received SCI format 0-1 indicate the values        P_(rsvp_RX) and prio_(RX), respectively according to Clause        [TBD] in [6, TS 38.213];    -   b) the RSRP measurement performed, according to clause 8.4.2.1        for the received SCI format 0-1, is higher than Th(prio_(RX));    -   c) the SCI format received in slot tor the same SCI format        which, if and only if the “Resource reservation period” field is        present in the received SCI format 0-1, is assumed to be        received in slot(s) t_(m+q×P) _(rsvp_RX) _(′) determines        according to clause [TBD] in [6, TS 38.213] the set of resource        blocks and slots which overlaps with R_(x,y+j×P) _(rsvp_TX) _(′)        for q=1, 2, . . . , Q and j=0, 1, . . . , C_(reset)−1. Here,        P_(rsvp_RX)′ is P_(rsvp_RX) converted to units of logical slots,

$Q = \left\lceil \frac{T_{scal}}{P_{rsvp\_ RX}} \right\rceil$if P_(rsvp_RX)<T_(scal) and n′−m≤P_(rsvp_RX)′, where t_(n′) ^(SL)=n ifslot n belongs to the set (t₀ ^(SL),t₁ ^(SL), . . . , t_(T) _(max)^(SL)), otherwise slot t_(n′) ^(SL) is the first slot after slot nbelonging to the set (t₀ ^(SL),t₁ ^(SL), . . . , t_(T) _(max) ^(SL));otherwise Q=1. T_(scai) is FFS.

7) If the number of candidate single-slot resources remaining in the setS_(A) is smaller than 0.2·M_(total), then Th(p_(i)) is increased by 3 dBfor each priority value Th(p_(i)) and the procedure continues with step4.

The UE shall report set S_(A) to higher layers.

8.1.5 UE Procedure for Determining Slots and Resource Blocks for PSSCHTransmission Associated with an SCI Format 0-1

The set of slots and resource blocks for PSSCH transmission isdetermined by the resource used for the PSCCH transmission containingthe associated SCI format 0-1, and fields “Frequency resourceassignment”, “Time resource assignment” of the associated SCI format 1as described below.

[TBD]

[ . . . ]

8.3 UE Procedure for Receiving the Physical Sidelink Shared Channel

For sidelink resource allocation mode 1, a UE upon detection of SCIformat 0-1 on PSCCH can decode PSSCH according to the detected SCIformat 0-2, and associated PSSCH resource configuration configured byhigher layers.

For sidelink resource allocation mode 2, a UE upon detection of SCIformat 0-1 on PSCCH can decode PSSCH according to the detected SCIformat 0-2, and associated PSSCH resource configuration configured byhigher layers.

3GPP TS 38.321 v16.0.0 specifies Medium Access Control (MAC) protocolspecification in NR as follows:

5.22 SL-SCH Data Transfer

5.22.1 SL-SCH Data Transmission

5.22.1.1 SL Grant Reception and SCI Transmission

Sidelink grant is received dynamically on the PDCCH, configuredsemi-persistently by RRC or autonomously selected by the MAC entity. TheMAC entity shall have a sidelink grant on an active SL BWP to determinea set of PSCCH duration(s) in which transmission of SCI occurs and a setof PSSCH duration(s) in which transmission of SL-SCH associated with theSCI occurs.

If the MAC entity has been configured by RRC to transmit using a SL-RNTIor SLCS-RNTI as indicated in TS 38.331 [5] or TS 36.331 [21], the MACentity shall for each PDCCH occasion and for each grant received forthis PDCCH occasion:

1> if a sidelink grant has been received on the PDCCH for the MACentity's SL-RNTI:

-   -   2> if the NDI received on the PDCCH has been not toggled        compared to the value in the previously received HARQ        information for the HARQ Process ID:        -   3> use the received sidelink grant to determine PSCCH            duration(s) and PSSCH duration(s) for one or more            retransmissions of a single MAC PDU for the corresponding            Sidelink process according to clause 8.1.2 of TS 38.214 [7];    -   2> else:        -   3> use the received sidelink grant to determine PSCCH            duration(s) and PSSCH duration(s) for initial transmission            and, if available, retransmission(s) of a single MAC PDU            according to clause 8.1.2 of TS 38.214 [7];    -   2> consider the received sidelink grant to be a configured        sidelink grant;    -   2> if a configured sidelink grant is available for        retransmission(s) of a MAC PDU which has been positively        acknowledged as specified in clause 5.22.1.3.3:        -   3> clear the PSCCH duration(s) and PSSCH duration(s)            corresponding to retransmission(s) of the MAC PDU from the            configured sidelink grant;

1> else if a sidelink grant has been received on the PDCCH for the MACentity's SLCS-RNTI:

-   -   2> if PDCCH contents indicate retransmission(s) for an activated        configured sidelink grant:        -   3> use the received sidelink grant to determine PSCCH            duration(s) and PSSCH duration(s) for one or more            retransmissions of a single MAC PDU according to clause            8.1.2 of TS 38.214 [7];    -   2> else if PDCCH contents indicate configured grant Type 2        deactivation for a configured sidelink grant:        -   3> clear the configured sidelink grant, if available;        -   3> trigger configured sidelink grant confirmation for the            configured sidelink grant;    -   2> else if PDCCH contents indicate configured grant Type 2        activation for a configured sidelink grant:        -   3> trigger configured sidelink grant confirmation for the            configured sidelink grant;        -   3> store the configured sidelink grant;        -   3> initialise or re-initialise the configured sidelink grant            to determine the set of PSCCH durations and the set of PSSCH            durations for transmissions of multiple MAC PDUs according            to clause 8.1.2 of TS 38.214 [7].

[ . . . ]

The MAC entity shall for each PSSCH duration:

1> for each configured sidelink grant occurring in this PSSCH duration:

-   -   2> if the MAC entity has been configured by RRC to transmit        using a SL-RNTI or SLCS-RNTI:        -   3> select a MCS which is, if configured, within the range            that is configured by RRC between sl-MinMCS-PSSCH and            sl-MaxMCS-PSSCH included in SL-ScheduledConfig;    -   2> else:        -   3> select a MCS which is, if configured, within the range            that is configured by RRC between sl-MinMCS-PSSCH and            sl-MaxMCS-PSSCH included in sl-PSSCH-TxConfigList and, if            configured by RRC, overlapped between sl-MinMCS-PSSCH and            sl-MaxMCS-PSSCH indicated in sl-CBR-PSSCH-TxConfigList for            the highest priority of the sidelink logical channel(s) in            the MAC PDU and the CBR measured by RRC according to TS            38.2xx [xx] if CBR measurement results are available or the            corresponding sl-defaultTxConfiglndex configured by RRC if            CBR measurement results are not available;

NOTE 3: MCS selection is up to UE implementation if the MCS or thecorresponding range is not configured by upper layers.

-   -   2> deliver the sidelink grant, the selected MCS, and the        associated HARQ information to the Sidelink HARQ Entity for this        PSSCH duration.

[ . . . ]

5.22.1.3 Sidelink HARQ Operation

5.22.1.3.1 Sidelink HARQ Entity

The MAC entity includes at most one Sidelink HARQ entity fortransmission on

SL-SCH, which maintains a number of parallel Sidelink processes.

The maximum number of transmitting Sidelink processes associated withthe Sidelink HARQ Entity is [TBD1]. A sidelink process may be configuredfor transmissions of multiple MAC PDUs. For transmissions of multipleMAC PDUs, the maximum number of transmitting Sidelink processesassociated with the Sidelink HARQ Entity is [TBD2].

A delivered sidelink grant and its associated Sidelink transmissioninformation are associated with a Sidelink process. Each Sidelinkprocess supports one TB.

For each sidelink grant, the Sidelink HARQ Entity shall:

1> if the MAC entity determines that the sidelink grant is used forinitial transmission; and

1> if no MAC PDU has been obtained:

NOTE 1: For the configured grant Type 1 and 2, whether a sidelink grantis used for initial transmission or retransmission is up to UEimplementation.

-   -   2> associate a Sidelink process to this grant, and for each        associated Sidelink process:        -   3> obtain the MAC PDU to transmit from the Multiplexing and            assembly entity, if any;        -   3> if a MAC PDU to transmit has been obtained:            -   4> determines Sidelink transmission information of the                TB for the source and destination pair of the MAC PDU as                follows:                -   5> set the Source Layer-1 ID to the 16 MSB of the                    Source Layer-2 ID of the MAC PDU;                -   5> set the Destination Layer-1 ID to the 8 MSB of                    the Destination Layer-2 ID of the MAC PDU;                -   5> consider the NDI to have been toggled and set the                    NDI to the toggled value;

NOTE 2: The initial value of the NDI set to the very first transmissionfor the Sidelink HARQ Entity is left to UE implementation.

-   -   5> associate the Sidelink process to a Sidelink process ID;

NOTE 3: How UE determine Sidelink process ID in SCI is left to UEimplementation for NR sidelink.

-   -   5> enable HARQ feedback, if sl-HARQ-FeedbackEnabled has been set        to Enabled for the logical channel(s) in the MAC PDU;    -   5> set the priority to the value of the highest priority of the        logical channel(s) and a MAC CE, if any, if included, in the MAC        PDU;    -   5> set the communication range to the value of the longest        communication range of the logical channel(s) in the MAC PDU, if        configured;    -   5> set the location information to the Zone_id determined as        specified in TS 38.331 [5], if configured;    -   4> deliver the MAC PDU, the sidelink grant and the Sidelink        transmission information of the TB to the associated Sidelink        process;    -   4> instruct the associated Sidelink process to trigger a new        transmission;    -   3> else:    -   4> flush the HARQ buffer of the associated Sidelink process.    -   1> else (i.e. retransmission):    -   2> identify the Sidelink process associated with this grant, and        for each associated Sidelink process:    -   3> if sl-MaxTransNum corresponding to the highest priority of        the logical channel(s) in the MAC PDU has been configured in        sl-CG-MaxTransNumList for the sidelink grant by RRC and the        maximum number of transmissions of the MAC PDU has been reached        to sl-MaxTransNum; or    -   3> if a positive acknowledgement to a transmission of the MAC        PDU has been received according to clause 5.22.1.3.3; or    -   1> if only a negative acknowledgement was enabled in the SCI and        no negative acknowledgement was received prioritized as        specified in clause 5.4.2.2, and the sidelink transmission is        prioritized over uplink transmission:    -   2> instruct the physical layer to transmit SCI according to the        stored sidelink grant with the associated Sidelink transmission        information;    -   2> instruct the physical layer to generate a transmission        according to the stored sidelink grant;    -   2> if sl-HARQ-FeedbackEnabled has been set to enabled for the        logical channel(s) in the MAC PDU:    -   3> instructs the physical layer to monitor PSFCH for the        transmission as specified in TS 38.2xx [x].    -   1> if this transmission corresponds to the last transmission of        the MAC PDU:    -   2> decrement SL_RESOURCE_RESELECTION_COUNTER by 1, if available.

The transmission of the MAC PDU is prioritized over uplink transmissionsof the MAC entity or the other MAC entity if the following conditionsare met:

1> if the MAC entity is not able to perform this sidelink transmissionsimultaneously with all uplink transmissions at the time of thetransmission, and

1> if uplink transmission is neither prioritized as specified in clause5.4.2.2 nor prioritized by upper layer according to TS [24.386] [xx];and

1> if the value of the highest priority of logical channel(s) and a MACCE in the MAC PDU is lower than sl-PrioritizationThres ifsl-PrioritizationThres is configured.

NOTE 4: If the MAC entity is not able to perform this sidelinktransmission simultaneously with all uplink transmissions as specifiedin clause 5.4.2.2 of TS 36.321 [22] at the time of the transmission, andprioritization-related information is not available prior to the time ofthis sidelink transmission due to processing time restriction, it is upto UE implementation whether this sidelink transmission is performed.

5.22.1.3.2 PSFCH Reception

The MAC entity shall for each PSSCH transmission:

1> if an acknowledgement corresponding to the transmission in clause5.22.1.3.1 is obtained from the physical layer:

-   -   2> deliver the acknowledgement to the corresponding Sidelink        HARQ entity for the Sidelink process;

1> else:

-   -   2> deliver a negative acknowledgement to the corresponding        Sidelink HARQ entity for the Sidelink process;

1> if sl-PUCCH-Config is configured by RRC:

2> instruct the physical layer to signal the acknowledgementcorresponding to the transmission on the PUCCH according to clause 16.5of TS 38.213 [x].

5.22.1.4 Multiplexing and Assembly

For PDU(s) associated with one SCI, MAC shall consider only logicalchannels with the same Source Layer-2 ID-Destination Layer-2 ID pair forone of unicast, groupcast and broadcast which is associated with thepair. Multiple transmissions for different Sidelink processes areallowed to be independently performed in different PSSCH durations.

5.22.1.4.1 Logical Channel Prioritization

5.22.1.4.1.1 General

The sidelink Logical Channel Prioritization procedure is appliedwhenever a new transmission is performed.

RRC controls the scheduling of sidelink data by signalling for eachlogical channel:

-   -   sl-Priority where an increasing priority value indicates a lower        priority level;    -   sl-PrioritisedBitRate which sets the sidelink Prioritized Bit        Rate (sPBR);    -   sl-BucketSizeDuration which sets the sidelink Bucket Size        Duration (sBSD).

RRC additionally controls the LCP procedure by configuring mappingrestrictions for each logical channel:

-   -   sl-configuredSLGrantType1Allowed which sets whether a configured        grant Type 1 can be used for sidelink transmission.

The following UE variable is used for the Logical channel prioritizationprocedure:

-   -   SBj which is maintained for each logical channel j.

The MAC entity shall initialize SBj of the logical channel to zero whenthe logical channel is established.

For each logical channel j, the MAC entity shall:

1> increment SBj by the product sPBR×T before every instance of the LCPprocedure, where T is the time elapsed since SBj was last incremented;

1> if the value of SBj is greater than the sidelink bucket size (i.e.sPBR×sBSD):

-   -   2> set SBj to the sidelink bucket size.

NOTE: The exact moment(s) when the UE updates SBj between LCP proceduresis up to UE implementation, as long as SBj is up to date at the timewhen a grant is processed by LCP.

5.22.1.4.1.2 Selection of Logical Channels

The MAC entity shall for each SCI corresponding to a new transmission:

1> select a Destination associated to one of unicast, groupcast andbroadcast, having the logical channel with the highest priority or theMAC CE, among the logical channels that satisfy all the followingconditions and MAC CE(s), if any, for the SL grant associated to theSCI:

-   -   2> SL data is available for transmission; and    -   2> SBj>0, in case there is any logical channel having SBj>0; and    -   2> sl-configuredSLGrantType1Allowed, if configured, is set to        true in case the SL grant is a Configured Grant Type 1.

NOTE: If multiple Destinations have the logical channels satisfying allconditions above with the same highest priority or if multipleDestinations have the MAC CE, which Destination is selected among themis up to UE implementation.

1> select the logical channels satisfying all the following conditionsamong the logical channels belonging to the selected Destination:

-   -   2> SL data is available for transmission; and    -   2> sl-configuredSLGrantType1Allowed, if configured, is set to        true in case the SL grant is a Configured Grant Type 1.

5.22.1.4.1.3 Allocation of Sidelink Resources

The MAC entity shall for each SCI corresponding to a new transmission:

1> allocate resources to the logical channels as follows:

-   -   2> logical channels selected in clause 5.22.1.4.1.2 for the SL        grant with SBj>0 are allocated resources in a decreasing        priority order. If the SL-PBR of a logical channel is set to        infinity, the MAC entity shall allocate resources for all the        data that is available for transmission on the logical channel        before meeting the sPBR of the lower priority logical        channel(s);    -   2> decrement SBj by the total size of MAC SDUs served to logical        channel j above;    -   2> if any resources remain, all the logical channels selected in        clause 5.22.1.4.1.2 are served in a strict decreasing priority        order (regardless of the value of SBj) until either the data for        that logical channel or the SL grant is exhausted, whichever        comes first. Logical channels configured with equal priority        should be served equally.

NOTE: The value of SBj can be negative.

The UE shall also follow the rules below during the SL schedulingprocedures above:

-   -   the UE should not segment an RLC SDU (or partially transmitted        SDU or retransmitted RLC PDU) if the whole SDU (or partially        transmitted SDU or retransmitted RLC PDU) fits into the        remaining resources of the associated MAC entity;    -   if the UE segments an RLC SDU from the logical channel, it shall        maximize the size of the segment to fill the grant of the        associated MAC entity as much as possible;    -   the UE should maximise the transmission of data;    -   if the MAC entity is given a sidelink grant size that is equal        to or larger than 12 bytes while having data available and        allowed (according to clause 5.22.1.4.1) for transmission, the        MAC entity shall not transmit only padding;    -   A logical channel configured with sl-HARQ-FeedbackEnabled set to        enabled and a logical channel configured with        sl-HARQ-FeedbackEnabled set to disabled cannot be multiplexed        into the same MAC PDU.

The MAC entity shall not generate a MAC PDU for the HARQ entity if thefollowing conditions are satisfied:

-   -   there is no Sidelink CSI Reporting MAC CE generated for this        PSSCH transmission as specified in clause 5.22.1.7; and    -   the MAC PDU includes zero MAC SDUs.

Logical channels shall be prioritised in accordance with the followingorder (highest priority listed first):

-   -   data from SCCH;    -   Sidelink CSI Reporting MAC CE;    -   data from any STCH.

5.22.1.4.2 Multiplexing of MAC SDUs

The MAC entity shall multiplex MAC SDUs in a MAC PDU according toclauses 5.22.1.3.1 and 6.1.6.

In the RAN1 #94 meeting (as discussed in 3GPP R1-1810051), RAN1 has thefollowing agreements about NR V2X:

Agreements:

-   -   At least two sidelink resource allocation modes are defined for        NR-V2X sidelink communication    -   Mode 1: Base station schedules sidelink resource(s) to be used        by UE for sidelink transmission(s)    -   Mode 2: UE determines (i.e. base station does not schedule)        sidelink transmission resource(s) within sidelink resources        configured by base station/network or pre-configured sidelink        resources

In the RAN1 #96bis meeting (as discussed in 3GPP R1-1905921), RAN1 hasthe following agreements about NR V2X:

Agreements:

-   -   It is supported, in a resource pool, that within the slots        associated with the resource pool, PSFCH resources can be        (pre)configured periodically with a period of N slot(s)        -   N is configurable, with the following values            -   1            -   At least one more value >1                -   FFS details        -   The configuration should also include the possibility of no            resource for PSFCH. In this case, HARQ feedback for all            transmissions in the resource pool is disabled    -   HARQ feedback for transmissions in a resource pool can only be        sent on PSFCH in the same resource pool

In the RAN1 #97 meeting (as discussed in 3GPP R1-1907973), RAN1 has thefollowing agreements about NR V2X as follows:

Agreements:

-   -   NR V2X Mode-2 supports resource reservation for feedback-based        PSSCH retransmissions by signaling associated with a prior        transmission of the same TB

Agreements:

-   -   RAN1 to further select between the following options of sidelink        resource reservation for blind retransmissions:        -   Option 1: A transmission can reserve resources for none,            one, or more than one blind retransmission        -   Option 2: A transmission can reserve resource for none or            one blind retransmission

Agreements:

-   -   Support a sub-channel as the minimum granularity in frequency        domain for the sensing for PSSCH resource selection    -   No additional sensing for other channels

Agreements:

-   -   For the period of N slot(s) of PSFCH resource, N=2 and N=4 are        additionally supported.

Agreements:

-   -   For a PSSCH transmission with its last symbol in slot n, when        the corresponding HARQ feedback is due for transmission, it is        expected to be in slot n+a where a is the smallest integer        larger than or equal to K with the condition that slot n+a        contains PSFCH resources.

Agreements:

-   -   At least for the case when the PSFCH in a slot is in response to        a single PSSCH:    -   Implicit mechanism is used to determine at least frequency        and/or code domain resource of PSFCH, within a configured        resource pool. At least the following parameters are used in the        implicit mechanism:        -   Slot index (FFS details) associated with PSCCH/PSSCH/PSFCH        -   Sub-channel(s) (FFS details) associated with PSCCH/PSSCH        -   Identifier (FFS details) to distinguish each RX UE in a            group for Option 2 groupcast HARQ feedback

In the RAN1 #98 meeting (as discussed in 3GPP R1-1909942), RAN1 has thefollowing agreements about NR V2X:

Agreements:

-   -   The resource (re-)selection procedure includes the following        steps        -   Step 1: Identification of candidate resources within the            resource selection window            -   FFS details        -   Step 2: Resource selection for (re-)transmission(s) from the            identified candidate resources            -   FFS details

In the RAN1 #99 meeting (as discussed in the Draft Report of 3GPP TSGRAN WG1 #99 V1.0.0), RAN1 has the following agreements about NR V2X:

Agreements:

-   -   From RAN1 perspective, a configured grant for SL can carry a TB        for which SL HARQ FB is enabled or disabled.        -   For any CG, if there is a possibility to carry a TB with SL            HARQ FB being enabled, there is always a corresponding PSFCH            configuration            -   A TB with SL HARQ FB is enabled can be carried by a CG                only if there is a corresponding PSFCH configuration for                the CG        -   For a TB with SL HARQ FB is disabled, up to RAN2 how to            utilize a CG for the transmission

R1-1913417

Agreements:

-   -   For dynamic grant, DCI contains HARQ ID and NDI.

Agreements:

-   -   For dynamic grant, DCI indicates the time-frequency resource        allocation with the signalling format used for SCI.        -   In addition, the starting sub-channel for initial            transmission is signalled in DCI.

Agreements:

-   -   To provide additional resources for retransmission upon        receiving a SL NACK report, a dynamic grant is used.        -   When the initial transmission of a TB is scheduled by a            dynamic grant, the CRC of the DCI carrying the dynamic grant            is scrambled using the SL RNTI introduced for DCI for a            dynamic grant.            -   The interpretation of NDI is the same as for Uu for                retransmission scheduled by DCI with CRC scrambled by                C-RNTI        -   When the initial transmission of a TB is scheduled by a            configured grant (type-1 or type-2), the CRC of the DCI            carrying the dynamic grant is scrambled using the SL RNTI            introduced for DCI for a configured grant type-2.            -   For interpretation of NDI, the Uu behavior for                retransmission scheduled by DCI with CRC scrambled by                CS-RNTI is reused.        -   (working assumption) The HARQ ID is used to identify the TB            for which resources for retransmission are provided (subject            to the indication of re-transmission via NDI)

Agreements:

-   -   At least the following parameters are part of a SL configured        grant configuration:        -   Configuration index of the CG        -   Time offset (for type-1 only)        -   Time-frequency allocation (for type-1 only)            -   Using the same format as in DCI.        -   Periodicity        -   The configured grant is associated with a single transmit            resource pool.        -   RAN2 can add other parameters if deemed necessary by RAN2    -   A UE in mode 1 is configured at least with one transmit resource        pool    -   For type-2 CG, the time-frequency allocation and the        configuration index of the CG are indicated in DCI.    -   All parameters for CG type 2 for activation DCI re-use the same        respective parameters configured for CG type 1, when applicable

Agreements:

-   -   Support W to be equal to 32 slots

Agreements:

-   -   On a per resource pool basis, when reservation of a sidelink        resource for an initial transmission of a TB at least by an SCI        associated with a different TB is enabled:    -   A period is additionally signalled in SCI and the same        reservation is applied with respect to resources indicated        within N_(MAX) within window W at subsequent periods    -   A set of possible period values is the following: 0, [1:99],        100, 200, 300, 400, 500, 600, 700, 800, 900, 1000 ms        -   <=4 bits are used in SCI to indicate a period        -   An actual set of values is (pre-)configured

Agreements:

-   -   In determining PSFCH candidate resources for a PSFCH format from        the starting sub-channel index and the slot index used for the        corresponding PSSCH for actual transmission,        -   Notation            -   S: the number of sub-channels in a slot            -   N: the number of PSSCH slots associated with a single                PSFCH slot            -   N_(F): the number of PRBs in the set (pre-)configured                for the actual PSFCH resources.        -   Within the set of PRBs (pre-)configured for the actual PSFCH            resources, the first Z PRBs are associated with the first            sub-channel in the first slot associated with the PSFCH            slot, the second Z PRBs are associated with the first            sub-channel in the second slot associated with the PSFCH            slot, and so on.            -   FFS when N_(F) is not a multiple of S*N        -   For a PSSCH, the candidate PSFCH resource is the set of PRBs            associated with            -   Option 1: the starting sub-channel and slot used for                that PSSCH.            -   Option 2: the sub-channel(s) and slot used for that                PSSCH

Agreements:

-   -   When a RX UE sends one bit HARQ-ACK in PSFCH        -   ACK and NACK are differentiated using different cyclic shift            of the same base sequence in the same PRB.        -   The cyclic shift corresponding to ACK is not defined/used            for groupcast option 1.

Working Assumption:

-   -   One PSFCH transmission can include up to X HARQ-ACK bits.        -   X=1

Agreements:

-   -   For Case 3 (PSFCH TX with multiple HARQ feedback to the same        UE),        -   For PSFCH resource period N=2 and 4,            -   Solution of Case 2 applies, i.e., select M PSFCH(s)                transmissions at least based on priority rule.

Working Assumption:

-   -   For the PSFCH candidate resource set with Z PRBs and Y cyclic        shift pairs in each PRB,        -   Each PSFCH resource is indexed in the manner of frequency            first and cyclic shift second.            -   FFS the order of cyclic shift indexing in a PRB.        -   PSFCH resource with the index ((K+M) mod (Z*Y)) is used for            PSFCH transmission of a RX UE.            -   K is the L1 source ID of the associated PSCCH/PSSCH.            -   M is 0 for unicast and groupcast feedback option 1 and M                is the member ID of the RX UE for groupcast feedback                option 2.        -   FFS whether to have the following restriction.            -   Groupcast HARQ feedback option 2 is not used if X>Z*Y (Y                denotes the number of PSFCH in a PRB).            -   Note: RAN1 assumes that the member ID M is an integer                between 0 and X−1.

In the RAN1 #100-e meeting (as discussed in the Draft Report of 3GPP TSGRAN WG1 #100-e V0.2.0), RAN1 has the following agreements about NR V2X:

Agreements:

-   -   For resource pool configuration, slots for a resource pool is        (pre-)configured with bitmap, which is applied with periodicity.

Agreements:

For derivation of the set of slots to be included in the resource pool,the baseline is the derivation with bitmap and periodicity based onSubclause 14.1.5 of TS36.213 with the following modifications.

-   -   FFS: Periodicity and L_bitmap value    -   The slot index is relative to slot #0 of the radio frame        corresponding to SFN 0 of the serving cell if serving cell        timing reference is in use, or DFN 0 otherwise    -   The following procedure is used.        -   The set includes all the slots except the following slots:            -   Slots in which SLSS resource is configured,            -   (Working assumption) slots not having at least Y-th,                (Y+1)-th, . . . , (Y+X−1)-th symbols in a slot                semi-statically for UL as indicated in                TDD-UL-DL-ConfigCommon, where                -   X is sl-LengthSymbols                -   Y is sl-StartSymbol            -   (Working assumption) reserved slots which are determined                by the similar steps in Subclause 14.1.5 of TS36.213

Agreements:

-   -   The mapping between the values of HPN signaled in DCI and HPN        signaled in SCI is fixed for a TB, and is up to UE        implementation.    -   For dynamic grant, the toggling of NDI in DCI is used as the        toggling of NDI in SCI for the first SL transmission scheduled        by the DCI. The SCI for the remaining transmissions scheduled by        the DCI, if any, have the NDI untoggled with respect to the        first SL transmission.

Agreements:

-   -   Only one new TB can be transmitted in one period of the        configured grant.        -   FFS any issue with retransmission spanning multiple periods    -   The DCI scheduling the retransmissions uses the HARQ process ID        corresponding to the first transmission of the TB, as agreed for        Q2.

Agreements:

-   -   The TX UE reports NACK to the gNB in the following cases:        -   When it does not transmit the corresponding PSCCH/PSSCH due            to intra-UE prioritization.        -   When it does not receive the corresponding PSFCH due to            intra-UE prioritization.

Agreements

-   -   For groupcast option 2 in the case where there are multiple        PSFCHs corresponding to multiple PSCCH/PSSCH transmissions of a        single TB, the TX UE reports ACK to the gNB if it has received        ACK at least once from each RX UE. Otherwise, it reports NACK to        the gNB.

Agreements

-   -   For groupcast option 2, the TX UE reports NACK to the gNB when        it does not detect some expected PSFCH.

Agreements

-   -   For configured grant, the TX UE reports ACK to the gNB in case        no PSCCH/PSSCH is transmitted in a set of resources.

NOTE: The rule in Q1 has precedence over this rule.

Agreements:

-   -   In Step 2, a UE ensures a minimum time gap Z=a+b between any two        selected resources of a TB where a HARQ feedback for the first        of these resources is expected        -   ‘a’ is a time gap between the end of the last symbol of the            PSSCH transmission of the first resource and the start of            the first symbol of the corresponding PSFCH reception            determined by resource pool configuration and higher layer            parameters of MinTimeGapPSFCH and periodPSFCHresource        -   ‘b’ is a time required for PSFCH reception and processing            plus sidelink retransmission preparation including            multiplexing of necessary physical channels and any            TX-RX/RX-TX switching time and is determined by UE            implementation

Agreements:

-   -   Time resource assignment in SCI uses an extended time domain RIV        mechanism as follows:    -   if N=1        -   TRIV=0    -   elseif N=2        -   TRIV=T₁    -   else        -   if (T₂−T₁−1)≤15            -   TRIV=30(T₂−T₁−1)+T₁+31        -   Else            -   TRIV=30(31−T₂+T₁)+62−T₁        -   end if    -   end if

where

-   -   N denotes the actual number of resources indicated    -   Ti denotes i-th resource time offset        -   for N=2, 1≤T₁≤31        -   for N=3, 1≤T₁≤30, T₁<T₂≤31

Agreements:

Agreement:

-   -   One of the following two options is (pre-)configured per        resource pool.        -   Option 1: The set of PRBs for the candidate PSFCH resource            is determined by the starting sub-channel and slot used for            that PSSCH.        -   Option 2: The set of PRBs for the candidate PSFCH resource            is determined by the sub-channel(s) and slot used for that            PSSCH.

One or multiple of following terminologies may be used hereafter:

-   -   BS: A network central unit or a network node in NR which is used        to control one or multiple TRPs which are associated with one or        multiple cells. Communication between BS and TRP(s) is via        fronthaul. BS could also be referred to as central unit (CU),        eNB, gNB, or NodeB.    -   TRP: A transmission and reception point provides network        coverage and directly communicates with UEs. TRP could also be        referred to as distributed unit (DU) or network node.    -   Cell: A cell is composed of one or multiple associated TRPs,        i.e. coverage of the cell is composed of coverage of all        associated TRP(s). One cell is controlled by one BS. Cell could        also be referred to as TRP group (TRPG).    -   NR-PDCCH: A channel carries downlink control signal which is        used to control communication between a UE and a network side. A        network transmits NR-PDCCH on configured control resource set        (CORESET) to the UE.    -   UL-control signal: An UL-control signal may be scheduling        request(SR), channel state information(CSI), HARQ-ACK/NACK for        downlink transmission.    -   Slot: A scheduling unit in NR. Each slot duration is 14 OFDM        symbols.    -   Mini-slot: A mini-slot is a scheduling unit with duration less        than 14 OFDM symbols.    -   Slot format information (SFI): Information of slot format of        symbols in a slot. A symbol in a slot may belong to following        type: downlink, uplink, unknown or other. The slot format of a        slot could at least convey transmission direction of symbols in        the slot.    -   DL common signal: Data channel carrying common information that        targets for multiple UEs in a cell or all UEs in a cell.        Examples of DL common signal could be system information,        paging, RAR.

One or multiple of following assumptions for network side may be usedhereafter:

-   -   Downlink timing of TRPs in the same cell are synchronized.    -   RRC layer of network side is in BS.

One or multiple of following assumptions for UE side may be usedhereafter:

-   -   There are at least two UE (RRC) states: connected state (or        called active state) and non-connected state (or called inactive        state or idle state). Inactive state may be an additional state        or belong to connected state or non-connected state.

In the RAN1 #94 meeting (as discussed in 3GPP R1-1810051), for NR V2Xtransmission, there are two sidelink resource allocation modes definedfor NR-V2X sidelink communication:

-   -   mode 1 is where base station or network node can schedule        sidelink resource(s) to be used by UE for sidelink        transmission(s);    -   mode 2 is where UE selects or determines (i.e. base station or        network node does not schedule) sidelink transmission        resource(s) within sidelink resources configured by base station        or network node or pre-configured sidelink resources.

For network scheduling mode, e.g. mode 1, the network node may transmita sidelink (SL) grant, e.g. Downlink Control Information (DCI) format3_0, on Uu interface for scheduling resources of Physical SidelinkControl Channel (PSCCH) and/or Physical Sidelink Shared Channel (PSSCH).The V2X UE may perform PSCCH and PSSCH transmissions on PC5 interface,in response to the received sidelink grant. The Uu interface could bethe wireless interface for communication between network node and UE.The PC5 interface could be the wireless interface for communication(directly) between UEs or devices.

For UE (autonomous) selection mode, e.g. mode 2, since transmissionresource is not scheduled or assigned via network node, the UE mayrequire performing sensing before selecting a resource for transmission(e.g., sensing-based transmission), in order to avoid resource collisionand interference from or to other UEs. Based on the result of sensingprocedure, the UE can determine or identify candidate resources withinthe resource selection window. The identified candidate resources may bereported to higher layers (of the UE). The UE may select one or multipleresources from the identified candidate resources to perform sidelinktransmission(s) from the UE. The transmission(s) from the UE may bePSCCH and/or PSSCH transmission.

Since NR V2X has requirement of high reliability and high throughput, itcan support SL HARQ feedback for unicast and/or groupcast. It means thata TX UE may transmit a sidelink data transmission to a RX UE, and thenthe RX UE may transmit SL HARQ feedback to the TX UE via PSFCHtransmission. If the SL HARQ feedback is ACK, it may mean that the RX UEreceives and decodes the sidelink data transmission successfully. Whenthe TX UE receives the SL HARQ feedback as ACK, the TX UE may transmitanother new sidelink data transmission to the RX UE if there areavailable data from the TX UE to the RX UE. If the SL HARQ feedback isNACK or the TX UE does not receive the SL HARQ feedback, it may mean theRX UE does not receive and/or decode the sidelink data transmissionsuccessfully. When the TX UE receives the SL HARQ feedback as NACK orthe TX UE does not receive the SL HARQ feedback, the TX UE mayretransmit the sidelink data transmission to the RX UE. Since thesidelink data retransmission carries the same data packet as thesidelink data transmission, the RX UE may combine the sidelink datatransmission and sidelink data retransmission and then perform decodingfor the data packet. The combining can increase possibility of decodingsuccessfully.

The RAN1 #96bis meeting (as discussed in 3GPP R1-1905921) supports thatin a resource pool, PSFCH resources are (pre)configured periodicallywith a period of slot(s), wherein N can be configured as 1, 2, or 4, asdiscussed in 3GPP R1-1905921 and R1-1907973. For a slot (pre)configuredwith PSFCH resources, the PSFCH resources in the slot are in the lastone or two sidelink symbols in the slot. Each PSFCH resource in the slotmay contain same number of symbols.

When TX UE acquires sidelink resources, the TX UE may select aDestination associated to one of unicast (e.g. a RX UE), groupcast (e.g.a sidelink group) and broadcast, having the logical channel with thehighest priority or the MAC CE, among the logical channels that haveavailable SL data for transmission. SBj>0 and/or Configured Grant Typemay be considered as well. When TX UE generates a MAC PDU fortransmission on the sidelink resources, it may be possible to multiplexSL data from one or more sidelink logical channels associated with thesame Destination. However, a logical channel configured withsl-HARQ-FeedbackEnabled set to enabled and a logical channel configuredwith sl-HARQ-FeedbackEnabled set to disabled cannot be multiplexed intothe same MAC PDU.

In the RAN1 #100-e meeting (as discussed in the Draft Report of 3GPP TSGRAN WG1 #100-e V0.2.0), it is agreed that in mode 2, a UE ensures aminimum time gap Z=a+b between any two selected resources of a TB wherea HARQ feedback for the first of these resources is expected. The value‘a’ is a time gap between the end of the last symbol of the PSSCHtransmission of the first resource and the start of the first symbol ofthe corresponding PSFCH reception determined by resource poolconfiguration and higher layer parameters of MinTimeGapPSFCH andperiodPSFCHresource. The value ‘b’ is a time required for PSFCHreception and processing plus sidelink retransmission preparationincluding multiplexing of necessary physical channels and anyTX-RX/RX-TX switching time and is determined by UE implementation. Inother words, the concept is that for a TB with SL HARQ feedback enabled,the TX UE needs to select one or more resources wherein time gap betweenany two selected resources larger than to equal to minimum time gap Z.Thus, after TX UE performs sidelink data transmission on one of theselected resources, the TX UE can determine, depending on associated SLHARQ feedback, whether to perform sidelink data retransmission in nextresource of the selected resources.

Currently, the minimum time gap Z for TB with SL HARQ feedback enabledis agreed for sidelink resource allocation mode 2. It is questionableabout the relationship between sidelink resource allocation mode 1 andthe minimum time gap Z. In mode 2, sidelink resources selection ordetermination for a TB and logical channel prioritization ordetermination (LCP) for multiplexing SL data in a TB are both performedin device/UE side. The main difference in mode 1 is that sidelinkresources for a TB are scheduled or assigned by network node, andlogical channel prioritization or determination for multiplexing SL datain a TB is performed in device/UE side.

Generally, the network node may expect which logical channel(s) will beprioritized or determined in the device or UE side, and then schedule orassign proper sidelink resources. For instance, if the network nodeexpects a logical channel with the highest priority or the MAC CE, amongthe logical channels that have available SL data for transmission indevice or UE side, is enabled with SL HARQ feedback, the network nodecan schedule or assign corresponding sidelink resources withconsideration on the minimum time gap Z. If the network node expects alogical channel with the highest priority or the MAC CE, among thelogical channels that have available SL data for transmission in deviceor UE side, is not enabled with SL HARQ feedback, the network node canschedule or assign corresponding sidelink resources withoutconsideration on the minimum time gap Z

However, the expectation in network node does not always seem to work.For example, the UE may have new SL data arrival and not yet report itto network node. As another example, since the modulation and codingscheme is determined by the device or UE, the network node does notclearly know how many SL data have been delivered before. Therefore,there may be some misaligned issues.

As an example, the network node schedules or assigns multiple sidelinkresources via a sidelink grant to a TX UE, wherein at least two of themultiple sidelink resources are with time gap less than the minimum timegap Z. However, the TX UE may generate a TB comprising sidelink datafrom SL logical channel(s) enabled with SL HARQ feedback. Thus, after TXUE performs sidelink data transmission on one of the multiple sidelinkresources, it may be impossible for the TX UE to determine, depending onassociated SL HARQ feedback, whether to perform sidelink dataretransmission in next one of the multiple sidelink resources.

In another case, the network node schedules or assigns multiple sidelinkresources via a sidelink grant to a TX UE, wherein any two of themultiple sidelink resources are with time gap larger than or equal tothe minimum time gap Z. However, the TX UE may generate a TB comprisingsidelink data from SL logical channel(s) disabled with SL HARQ feedback.If the SL logical channel(s) comprises urgent data or low latency data,the sidelink transmission(s) on the multiple sidelink resources mayinduce unnecessary latency.

In view of these misaligned issues, some concepts, mechanisms, methods,or embodiments are provided below.

Method a

The general concept of Method a is that the minimum time gap Z isconsidered for sidelink resource(s) in mode 1. Network node may(implicitly) control/schedule TX UE for selecting SL data from either SLlogical channel(s) (or MAC PDU) with enabled SL HARQ feedback or SLlogical channel(s) (or MAC PDU) with disabled SL HARQ feedback.

A TX UE may receive a SL grant from a network node. The SL grant mayschedule/assign multiple sidelink resources. The TX UE may check whethertime gap of any two (adjacent, neighbor, or consecutive) scheduled orassigned sidelink resources is larger than or equal to the minimum timegap Z.

In one embodiment, if (all) time gap of any two (adjacent, neighbor, orconsecutive) scheduled or assigned sidelink resources is larger than orequal to the minimum time gap Z, the TX UE may determine to select(only) SL logical channel(s) (or MAC PDU) with enabled SL HARQ feedback.The TX UE may be allowed to select SL logical channel(s) (or MAC PDU)with enabled SL HARQ feedback. The TX UE may generate a TB, whichcomprises or multiplexes SL data from (only) SL logical channel(s) (orMAC PDU) with enabled SL HARQ feedback. The TX UE may preclude orexclude from selecting SL logical channel(s) (or MAC PDU) with disabledSL HARQ feedback. The TX UE may generate a TB, which precludes orexcludes from comprising or multiplexing SL data from SL logicalchannel(s) (or MAC PDU) with disabled SL HARQ feedback. In other words,the Logical Channel Prioritization (LCP) for the Transport Block (TB)may be performed among (only) SL logical channel(s) (or MAC PDU) withenabled SL HARQ feedback. In one embodiment, the LCP for the TB may beperformed among (only) SL logical channel(s) (or MAC PDU) with enabledSL HARQ feedback and with available SL data and with SBj>0.

In one embodiment, if at least a time gap of any two (adjacent,neighbor, or consecutive) scheduled or assigned sidelink resources isless than the minimum time gap Z, the TX UE may determine to select(only) SL logical channel(s) (or MAC PDU) with disabled SL HARQfeedback. The TX UE may generate a TB, which comprises or multiplexes SLdata from (only) SL logical channel(s) (or MAC PDU) with disabled SLHARQ feedback. The TX UE may preclude or exclude from selecting SLlogical channel(s) (or MAC PDU) with enabled SL HARQ feedback. The TX UEmay generate a TB, which precludes or excludes from comprising ormultiplexing SL data from SL logical channel(s) (or MAC PDU) withenabled SL HARQ feedback. In other words, the LCP for the TB may beperformed among (only) SL logical channel(s) (or MAC PDU) with disabledSL HARQ feedback. In one embodiment, the LCP for the TB may be performedamong (only) SL logical channel(s) (or MAC PDU) with disabled SL HARQfeedback and with available SL data and with SBj>0.

In one embodiment, if at least a time gap of any two (adjacent,neighbor, or consecutive) scheduled or assigned sidelink resources islarger than or equal to the minimum time gap Z, the TX UE may determineto select (only) SL logical channel(s) (or MAC PDU) with enabled SL HARQfeedback. The TX UE may be allowed to select SL logical channel(s) (orMAC PDU) with enabled SL HARQ feedback. The TX UE may generate a TB,which comprises or multiplexes SL data from (only) SL logical channel(s)(or MAC PDU) with enabled SL HARQ feedback. The TX UE may preclude orexclude from selecting SL logical channel(s) (or MAC PDU) with disabledSL HARQ feedback. The TX UE may generate a TB, which precludes orexcludes from comprising or multiplexing SL data from SL logicalchannel(s) (or MAC PDU) with disabled SL HARQ feedback. In other words,the LCP for the TB may be performed among (only) SL logical channel(s)(or MAC PDU) with enabled SL HARQ feedback. In one embodiment, the LCPfor the TB may be performed among (only) SL logical channel(s) (or MACPDU) with enabled SL HARQ feedback and with available SL data and withSBj>0.

In one embodiment, if (all) time gap of any two (adjacent, neighbor, orconsecutive) scheduled or assigned sidelink resources is less than theminimum time gap Z, the TX UE may determine to select (only) SL logicalchannel(s) (or MAC PDU) with disabled SL HARQ feedback. The TX UE maygenerate a TB, which comprises or multiplexes SL data from (only) SLlogical channel(s) (or MAC PDU) with disabled SL HARQ feedback. The TXUE may preclude or exclude from selecting SL logical channel(s) (or MACPDU) with enabled SL HARQ feedback. The TX UE may generate a TB, whichprecludes or excludes from comprising or multiplexing SL data from SLlogical channel(s) (or MAC PDU) with enabled SL HARQ feedback. In otherwords, the LCP for the TB may be performed among (only) SL logicalchannel(s) (or MAC PDU) with disabled SL HARQ feedback. In oneembodiment, the LCP for the TB may be performed among (only) SL logicalchannel(s) (or MAC PDU) with disabled SL HARQ feedback and withavailable SL data and with SBj>0.

In one embodiment, the TX UE may perform one or more sidelinktransmission(s) on one or more of the multiple sidelink resourcesscheduled or assigned by the SL grant. The one or more sidelinktransmission comprises or delivers the generated TB.

Method b

The general direction of Method b is that the minimum time gap Z is notconsidered for sidelink resource(s) in mode 1 for TB generation. A TX UEmay receive a SL grant from a network node. The SL grant may schedule orassign multiple sidelink resources. In one embodiment, the TX UE maygenerate a TB. The TX UE may perform one or more sidelinktransmission(s) on one or more of the multiple sidelink resourcesscheduled or assigned by the SL grant. The one or more sidelinktransmission comprises/delivers the generated TB.

In one embodiment, when the TX UE generates the TB for sidelinktransmission, the TX UE may not check whether time gap of any two(adjacent, neighbor, or consecutive) scheduled or assigned sidelinkresources is larger than or equal to the minimum time gap Z. The TX UEmay perform LCP for the TB among SL logical channel(s)logical channel(s)(or MAC PDU) with enabled SL HARQ feedback and SL logicalchannel(s)logical channel(s) (or MAC PDU) with disabled SL HARQfeedback. The TX UE may perform LCP for the TB among SL logicalchannel(s) (or MAC PDU) without considering enabled or disabled SL HARQfeedback. The TX UE may perform LCP for the TB among SL logicalchannel(s)logical channel(s) (or MAC PDU) with available SL data andwith SBj>0 and without considering enabled or disabled SL HARQ feedback.

There may be at least four embodiments:

First Embodiment

In the first embodiment, (all) time gap of any two (adjacent, neighbor,or consecutive) scheduled or assigned sidelink resources may be largerthan or equal to the minimum time gap Z, and the TX UE may generate theTB, which comprises or multiplexes SL data from (only) SL logicalchannel(s)logical channel(s) (or MAC PDU) with enabled SL HARQ feedback.It may mean that the expectation of network node aligns to TX UE'ssidelink buffer status. In one embodiment, the TX UE may transmit one ormore sidelink control information to schedule the one or more sidelinkdata transmissions. The TX UE may transmit the one or more sidelinkcontrol information to schedule, indicate, or reserve the one or more ofthe multiple sidelink resources. In one embodiment, the one or moresidelink control information may indicate RX UE to transmit SL HARQfeedback.

As shown in exemplary FIG. 8a , PSSCH1 and/or PSSCH2 may comprise thesame TB, which comprises or multiplexes SL data from SL logicalchannel(s)logical channel(s) (or MAC PDU) with enabled SL HARQ feedback.SCI1 and/or SCI2 may indicate RX UE to transmit SL HARQ feedback.

As shown in exemplary FIG. 9a , PSSCH1, PSSCH 2, and/or PSSCH 3 maycomprise the same TB, which comprises or multiplexes SL data from SLlogical channel(s)logical channel(s) (or MAC PDU) with enabled SL HARQfeedback. SCI1, SCI2, and/or SCI3 may indicate RX UE to transmit SL HARQfeedback.

Second Embodiment

In the second embodiment, at least a time gap of any two (adjacent,neighbor, or consecutive) scheduled or assigned sidelink resources maybe less than the minimum time gap Z, and the TX UE may generate the TB,which comprises or multiplexes SL data from (only) SL logicalchannel(s)logical channel(s) (or MAC PDU) with disabled SL HARQfeedback. It may mean that the expectation of network node aligns to TXUE's sidelink buffer status. In one embodiment, the TX UE may transmitone or more sidelink control information to schedule the one or moresidelink data transmissions. The TX UE may transmit the one or moresidelink control information to schedule, indicate, or reserve the oneor more of the multiple sidelink resources. The one or more sidelinkcontrol information may indicate RX UE not to transmit SL HARQ feedback.

As shown in exemplary FIG. 8-b, PSSCH1 and/or PSSCH 2 may comprise thesame TB, which comprises or multiplexes SL data from SL logicalchannel(s)logical channel(s) (or MAC PDU) with disabled SL HARQfeedback. SCI1 and/or SCI2 may indicate RX UE not to transmit SL HARQfeedback.

As shown in exemplary FIG. 9-b, 9-c, or 9-d, PSSCH1, PSSCH 2, and/orPSSCH 3 may comprise the same TB, which comprises or multiplexes SL datafrom SL logical channel(s) (or MAC PDU) with disabled SL HARQ feedback.SCI1, SCI2, and/or SCI3 may indicate RX UE not to transmit SL HARQfeedback.

Third Embodiment

In third embodiment, at least a time gap of any two (adjacent, neighbor,or consecutive) scheduled or assigned sidelink resources may be lessthan the minimum time gap Z, and the TX UE may generate the TB, whichcomprises or multiplexes SL data from (only) SL logicalchannel(s)logical channel(s) (or MAC PDU) with enabled SL HARQ feedback.It may mean that the expectation of network node does not align to TXUE's sidelink buffer status.

As shown in exemplary FIG. 8-b, PSSCH1 and/or PSSCH 2 may comprise thesame TB, which comprises or multiplexes SL data from SL logicalchannel(s)logical channel(s) (or MAC PDU) with enabled SL HARQ feedback.

As shown in exemplary FIG. 9-b, 9-c, or 9-d, PSSCH1, PSSCH 2, and/orPSSCH 3 may comprise the same TB, which comprises or multiplexes SL datafrom SL logical channel(s)logical channel(s) (or MAC PDU) with enabledSL HARQ feedback.

In one embodiment, the TX UE may transmit one or more sidelink controlinformation to schedule the one or more sidelink data transmissions. TheTX UE may transmit the one or more sidelink control information toschedule, indicate, or reserve the one or more of the multiple sidelinkresources.

In one embodiment, (all) the one or more sidelink control informationmay indicate RX UE to transmit SL HARQ feedback. It may mean that RX UEmay transmit one or more SL HARQ feedback transmissions associated withthe one or more sidelink data transmission respectively. The RX UE maytransmit one or more SL HARQ feedback transmissions on one or moresidelink feedback resources, which are associated with the one or moresidelink resources respectively. As shown in exemplary FIG. 8-b, SCI1and/or SCI2 may indicate RX UE to transmit SL HARQ feedback. As shown inexemplary FIG. 9-b, 9-c, or 9-d, SCI1, SCI2, and/or SCI3 may indicate RXUE to transmit SL HARQ feedback.

Additionally or alternatively, the last sidelink control information (intime domain) among the one or more sidelink control information mayindicate RX UE to transmit SL HARQ feedback. The other sidelink controlinformation(s) may indicate RX UE not to transmit SL HARQ feedback. Itmay mean that RX UE may transmit one SL HARQ feedback transmissionassociated with the last one sidelink data transmission (in timedomain). The RX UE may transmit one SL HARQ feedback transmissions onone sidelink feedback resource, which is associated with the last onesidelink resource (in time domain). As shown in exemplary FIG. 8-b, SCI1may indicate RX UE not to transmit SL HARQ feedback, and/or SCI2 mayindicate RX UE to transmit SL HARQ feedback. As shown in exemplary FIG.9-b, 9-c, or 9-d, SCI1 and/or SCI2 may indicate RX UE not to transmit SLHARQ feedback, and/or SCI3 may indicate RX UE to transmit SL HARQfeedback.

Additional or alternatively, the last sidelink control information (intime domain) among the one or more sidelink control information, beforeTX UE reports corresponding HARQ report to network node (consideringprocessing time to generate the corresponding HARQ report), may indicateRX UE to transmit SL HARQ feedback. The other sidelink controlinformation(s) may indicate RX UE not to transmit SL HARQ feedback. Itmay mean that RX UE may transmit one SL HARQ feedback transmissionassociated with the last one sidelink data transmission (in timedomain), before TX UE reports corresponding HARQ report to network node(considering processing time to generate the corresponding HARQ report).The RX UE may transmit one SL HARQ feedback transmissions on onesidelink feedback resource, which is associated with the last onesidelink resource (in time domain).

In one embodiment, TX UE reports corresponding HARQ report to networknode, wherein corresponding HARQ report is set based on SL HARQ feedbackassociated with the last one sidelink resource. The processing time togenerate the corresponding HARQ report may comprise any of SL HARQfeedback generation time of RX UE, SL HARQ feedback reception ordecoding time of TX UE, and/or corresponding HARQ report generation timeof TX UE. In one embodiment, the processing time to generate thecorresponding HARQ report may equal to the minimum time gap Z.

As shown in exemplary FIG. 8-b, if TX UE reports corresponding HARQreport to network node in time occasion after SCI 2, SCI1 may indicateRX UE not to transmit SL HARQ feedback, and/or SCI2 may indicate RX UEto transmit SL HARQ feedback. As shown in exemplary FIG. 9-b, 9-c, or9-d, if TX UE reports corresponding HARQ report to network node in timeoccasion after SCI 3, SCI1 and/or SCI2 may indicate RX UE not totransmit SL HARQ feedback, and/or SCI3 may indicate RX UE to transmit SLHARQ feedback. If TX UE reports corresponding HARQ report to networknode in a time occasion between SCI2 and SCI3 and in a time occasionafter SCI 3, SCI1 may indicate RX UE not to transmit SL HARQ feedback,and/or SCI2 and/or SCI3 may indicate RX UE to transmit SL HARQ feedback.

Additional or alternatively, if time gap of two adjacent, neighbor, orconsecutive scheduled or assigned sidelink resources is larger than orequal to the minimum time gap Z, the sidelink control information in thefirst one or the earlier one (in time domain) of the two adjacent,neighbor, or consecutive scheduled or assigned resources may indicate RXUE to transmit SL HARQ feedback. If time gap of two adjacent, neighbor,or consecutive scheduled or assigned resources is less than the minimumtime gap Z, the sidelink control information in the first one or theearlier one (in time domain) of the two adjacent, neighbor, orconsecutive scheduled or assigned resources may indicate RX UE not totransmit SL HARQ feedback.

The sidelink control information in the last one (in time domain) or thelatter one of the one or more sidelink resources may indicate RX UE totransmit SL HARQ feedback. It may mean that the TX UE requests RX UE totransmit SL HARQ feedback if time gap to next sidelink resourcesatisfies the minimum time gap Z. If time gap to next sidelink resourcedoes not satisfy the minimum time gap Z, TX UE may not request RX UE totransmit SL HARQ feedback, since TX UE cannot determine whether toperform sidelink data transmission in the next sidelink resourcedepending on the SL HARQ feedback. The RX UE may transmit one SL HARQfeedback transmission associated with the one sidelink data transmissionif the associated sidelink control information indicates to transmit SLHARQ feedback. The RX UE may transmit one SL HARQ feedback transmissionon one sidelink feedback resource, which is associated with the onesidelink resource if the associated sidelink control informationindicates to transmit SL HARQ feedback.

As shown in exemplary FIG. 8-b, SCI1 may indicate RX UE not to transmitSL HARQ feedback, and/or SCI2 may indicate RX UE to transmit SL HARQfeedback. As shown in exemplary FIG. 9-b, SCI1 and/or SCI3 may indicateRX UE to transmit SL HARQ feedback, and/or SCI2 may indicate RX UE notto transmit SL HARQ feedback. As shown in FIG. 9-c, SCI2 and/or SCI3 mayindicate RX UE to transmit SL HARQ feedback, and/or SCI1 may indicate RXUE not to transmit SL HARQ feedback. As shown in FIG. 9-d, SCI1 and/orSCI2 may indicate RX UE not to transmit SL HARQ feedback, and/or SCI3may indicate RX UE to transmit SL HARQ feedback.

Additionally or alternatively, if time gap of two adjacent, neighbor, orconsecutive scheduled or assigned sidelink resources is less than theminimum time gap Z, and if two sidelink feedback resources associatedwith the two adjacent, neighbor, or consecutive scheduled or assignedresources are in the same slot, sidelink control information in thefirst one or the earlier one (in time domain) of the two adjacent,neighbor, or consecutive scheduled or assigned sidelink resources mayindicate RX UE not to transmit SL HARQ feedback. Sidelink controlinformation in the second one or the latter one (in time domain) of thetwo adjacent, neighbor, or consecutive scheduled or assigned resourcesmay indicate RX UE to transmit SL HARQ feedback.

Additionally or alternatively, if time gap of two adjacent, neighbor, orconsecutive scheduled or assigned sidelink resources is less than theminimum time gap Z, and if two sidelink feedback resources associatedwith the two adjacent, neighbor, or consecutive scheduled or assignedsidelink resources are in the same slot, sidelink control information inthe second one or the latter one (in time domain) of the two adjacent,neighbor, or consecutive scheduled or assigned sidelink resources mayindicate RX UE not to transmit SL HARQ feedback (except the second oneof the two adjacent, neighbor, or consecutive scheduled or assignedresources is the last resource scheduled or assigned by the SL grant).Sidelink control information in the first one or the earlier one (intime domain) of the two adjacent, neighbor, or consecutive scheduled orassigned resources may indicate RX UE to transmit SL HARQ feedback. Thisis because it is sufficient for RX UE to transmit, in one slot, one SLHARQ feedback associated with the TB.

Fourth Embodiment

In fourth embodiment, (all) time gap of any two (adjacent, neighbor, orconsecutive) scheduled or assigned sidelink resources may be larger thanor equal to the minimum time gap Z, and TX UE may generate the TB, whichcomprises or multiplexes SL data from (only) SL logicalchannel(s)logical channel(s) (or MAC PDU) with disabled SL HARQfeedback. It may mean that the expectation of network node does notalign to TX UE's sidelink buffer status. In one embodiment, TX UE maytransmit one or more sidelink control information to schedule the one ormore sidelink data transmissions. TX UE may transmit the one or moresidelink control information to schedule, indicate, or reserve the oneor more of the multiple sidelink resources. In one embodiment, the oneor more sidelink control information may indicate RX UE to transmit SLHARQ feedback.

As shown in exemplary FIG. 8-a, PSSCH1 and/or PSSCH 2 may comprise thesame TB, which comprises or multiplexes SL data from SL logicalchannel(s) (or MAC PDU) with disabled SL HARQ feedback. SCI1 and/or SCI2may indicate RX UE not to transmit SL HARQ feedback. As shown inexemplary FIG. 9-a, PSSCH1, PSSCH2, and/or PSSCH3 may comprise the sameTB, which comprises or multiplexes SL data from SL logical channel(s)(or MAC PDU) with disabled SL HARQ feedback. SCI1, SCI2, and/or SCI3 mayindicate RX UE not to transmit SL HARQ feedback.

Additionally or alternatively, there may be another four embodiments:

Fifth Embodiment

In the fifth embodiment, at least a time gap of any two (adjacent,neighbor, or consecutive) scheduled or assigned sidelink resources maybe larger than or equal to the minimum time gap Z, and the TX UE maygenerate the TB, which comprises or multiplexes SL data from (only) SLlogical channel(s) (or MAC PDU) with enabled SL HARQ feedback. It maymean that the expectation of network node aligns to TX UE's sidelinkbuffer status. In one embodiment, the TX UE may transmit one or moresidelink control information to schedule the one or more sidelink datatransmissions. The TX UE may transmit the one or more sidelink controlinformation to schedule, indicate, or reserve the one or more of themultiple sidelink resources. In one embodiment, the one or more sidelinkcontrol information may indicate RX UE to transmit SL HARQ feedback.

As shown in exemplary FIG. 8-a, PSSCH1 and/or PSSCH 2 may comprise thesame TB, which comprises or multiplexes SL data from SL logicalchannel(s)logical channel(s) (or MAC PDU) with enabled SL HARQ feedback.SCI1 and/or SCI2 may indicate RX UE to transmit SL HARQ feedback. Asshown in exemplary FIG. 9-a, 9-b, or 9-c, PSSCH1, PSSCH2, and/or PSSCH3may comprise the same TB, which comprises or multiplexes SL data from SLlogical channel(s)logical channel(s) (or MAC PDU) with enabled SL HARQfeedback. SCI1, SCI2, and/or SCI3 may indicate RX UE to transmit SL HARQfeedback.

Sixth Embodiment

In sixth embodiment, (all) time gap of any two (adjacent, neighbor, orconsecutive) scheduled or assigned sidelink resources may be less thanthe minimum time gap Z, and TX UE may generate the TB, which comprisesor multiplexes SL data from (only) SL logical channel(s) (or MAC PDU)with disabled SL HARQ feedback. It may mean that the expectation ofnetwork node aligns to TX UE's sidelink buffer status. In oneembodiment, the TX UE may transmit one or more sidelink controlinformation to schedule the one or more sidelink data transmissions. TheTX UE may transmit the one or more sidelink control information toschedule, indicate, or reserve the one or more of the multiple sidelinkresources. In one embodiment, the one or more sidelink controlinformation may indicate RX UE not to transmit SL HARQ feedback.

As shown in exemplary FIG. 8-b, PSSCH1 and/or PSSCH 2 may comprise thesame TB, which comprises or multiplexes SL data from SL logicalchannel(s)logical channel(s) (or MAC PDU) with disabled SL HARQfeedback. SCI1 and/or SCI2 may indicate RX UE not to transmit SL HARQfeedback.

As shown in exemplary FIG. 9-b, PSSCH1, PSSCH2, and/or PSSCH3 maycomprise the same TB, which comprises or multiplexes SL data from SLlogical channel(s) (or MAC PDU) with disabled SL HARQ feedback. SCI1,SCI2, and/or SCI3 may indicate RX UE not to transmit SL HARQ feedback.

Seventh Embodiment

In seventh embodiment, (all) time gap of any two (adjacent, neighbor, orconsecutive) scheduled or assigned sidelink resources may be less thanthe minimum time gap Z, and TX UE may generate the TB, which comprisesor multiplexes SL data from (only) SL logical channel(s) (or MAC PDU)with enabled SL HARQ feedback. It may mean that the expectation ofnetwork node does not align to TX UE's sidelink buffer status.

As shown in exemplary FIG. 9-b, PSSCH1 and/or PSSCH 2 may comprise thesame TB, which comprises or multiplexes SL data from SL logicalchannel(s) (or MAC PDU) with enabled SL HARQ feedback. As shown inexemplary FIG. 9-d, PSSCH1, PSSCH 2, and/or PSSCH 3 may comprise thesame TB, which comprises or multiplexes SL data from SL logicalchannel(s)logical channel(s) (or MAC PDU) with enabled SL HARQ feedback.

In one embodiment, the TX UE may transmit one or more sidelink controlinformation to schedule the one or more sidelink data transmissions. TheTX UE may transmit the one or more sidelink control information toschedule, indicate, or reserve the one or more of the multiple sidelinkresources.

In one embodiment, (all) the one or more sidelink control informationmay indicate RX UE to transmit SL HARQ feedback. It may mean that RX UEmay transmit one or more SL HARQ feedback transmissions associated withthe one or more sidelink data transmission respectively. The RX UE maytransmit one or more SL HARQ feedback transmissions on one or moresidelink feedback resources, which are associated with the one or moresidelink resources respectively. As shown in exemplary FIG. 8-b, SCI1and/or SCI2 may indicate RX UE to transmit SL HARQ feedback. As shown inexemplary FIG. 9-d, SCI1, SCI2, and/or SCI3 may indicate RX UE totransmit SL HARQ feedback.

Additionally or alternatively, the last sidelink control information (intime domain) among the one or more sidelink control information mayindicate RX UE to transmit SL HARQ feedback. The other sidelink controlinformation(s) may indicate RX UE not to transmit SL HARQ feedback. Itmay mean that RX UE may transmit one SL HARQ feedback transmissionassociated with the last one sidelink data transmission (in timedomain). The RX UE may transmit one SL HARQ feedback transmissions onone sidelink feedback resource, which is associated with the last onesidelink resource (in time domain).

As shown in exemplary FIG. 8-b, SCI1 may indicate RX UE not to transmitSL HARQ feedback, and/or SCI2 may indicate RX UE to transmit SL HARQfeedback. As shown in exemplary FIG. 9-d, SCI1 and/or SCI2 may indicateRX UE not to transmit SL HARQ feedback, and/or SCI3 may indicate RX UEto transmit SL HARQ feedback.

Additionally or alternatively, the last sidelink control information (intime domain) among the one or more sidelink control information, beforeTX UE reports corresponding HARQ report to network node (consideringprocessing time to generate the corresponding HARQ report), may indicateRX UE to transmit SL HARQ feedback. The other sidelink controlinformation(s) may indicate RX UE not to transmit SL HARQ feedback. Itmay mean that RX UE may transmit one SL HARQ feedback transmissionassociated with the last one sidelink data transmission (in timedomain), before TX UE reports corresponding HARQ report to network node(considering processing time to generate the corresponding HARQ report).RX UE may transmit one SL HARQ feedback transmissions on one sidelinkfeedback resource, which is associated with the last one sidelinkresource (in time domain).

In one embodiment, TX UE may report corresponding HARQ report to networknode, wherein corresponding HARQ report is set based on SL HARQ feedbackassociated with the last one sidelink resource. The processing time togenerate the corresponding HARQ report may comprise any of SL HARQfeedback generation time of RX UE, SL HARQ feedback reception ordecoding time of TX UE, and/or corresponding HARQ report generation timeof TX UE. In one embodiment, the processing time to generate thecorresponding HARQ report may equal to the minimum time gap Z.

As shown in exemplary FIG. 8-b, if TX UE reports corresponding HARQreport to network node in time occasion after SCI 2, SCI1 may indicateRX UE not to transmit SL HARQ feedback, and/or SCI2 may indicate RX UEto transmit SL HARQ feedback. As shown in exemplary FIG. 9-d, if TX UEreports corresponding HARQ report to network node in time occasion afterSCI 3, SCI1 and/or SCI2 may indicate RX UE not to transmit SL HARQfeedback, and/or SCI3 may indicate RX UE to transmit SL HARQ feedback.If TX UE reports corresponding HARQ report to network node in a timeoccasion between SCI2 and SCI3 and in a time occasion after SCI 3, SCI1may indicate RX UE not to transmit SL HARQ feedback, and/or SCI2 and/orSCI3 may indicate RX UE to transmit SL HARQ feedback.

Additionally or alternatively, if time gap of two adjacent, neighbor, orconsecutive scheduled or assigned resources is less than the minimumtime gap Z, and if two sidelink feedback resources associated with thetwo adjacent, neighbor, or consecutive scheduled or assigned resourcesare in the same slot, sidelink control information in the first one orthe earlier one (in time domain) of the two adjacent, neighbored, orconsecutive scheduled or assigned resources may indicate RX UE not totransmit SL HARQ feedback. Sidelink control information in the secondone or the latter one (in time domain) of the two adjacent, neighbor, orconsecutive scheduled or assigned resources may indicate RX UE totransmit SL HARQ feedback.

Additionally or alternatively, if time gap of two adjacent, neighbor, orconsecutive scheduled or assigned resources is less than the minimumtime gap Z, and if two sidelink feedback resources associated with thetwo adjacent, neighbor, or consecutive scheduled or assigned resourcesare in the same slot, sidelink control information in the second one orthe latter one (in time domain) of the two adjacent, neighbor, orconsecutive scheduled or assigned resources may indicate RX UE not totransmit SL HARQ feedback (except the second one of the two adjacent,neighbor, or consecutive scheduled or assigned resources is the lastresource scheduled/assigned by the SL grant). Sidelink controlinformation in the first one or the earlier one (in time domain) of thetwo adjacent, neighbor, or consecutive scheduled or assigned resourcesmay indicate RX UE to transmit SL HARQ feedback. This is because it issufficient for the RX UE to transmit, in one slot, one SL HARQ feedbackassociated with the TB.

Eighth Embodiment

In the eighth embodiment, at least a time gap of any two (adjacent,neighbor, or consecutive) scheduled or assigned sidelink resources maybe larger than or equal to the minimum time gap Z, and TX UE maygenerate the TB, which comprises or multiplexes SL data from (only) SLlogical channel(s) (or MAC PDU) with disabled SL HARQ feedback. It maymean that the expectation of network node does not align to TX UE'ssidelink buffer status. In one embodiment, the TX UE may transmit one ormore sidelink control information to schedule the one or more sidelinkdata transmissions. The TX UE may transmit the one or more sidelinkcontrol information to schedule, indicate, or reserve the one or more ofthe multiple sidelink resources. In one embodiment, the one or moresidelink control information may indicate RX UE to transmit SL HARQfeedback.

As shown in exemplary FIG. 8-a, PSSCH1 and/or PSSCH 2 may comprise thesame TB, which comprises or multiplexes SL data from SL logicalchannel(s) (or MAC PDU) with disabled SL HARQ feedback. SCI1 and/or SCI2may indicate RX UE not to transmit SL HARQ feedback.

As shown in exemplary FIG. 9-a, 9-b, or 9-c, PSSCH1, PSSCH2, and/orPSSCH3 may comprise the same TB, which comprises or multiplexes SL datafrom SL logical channel(s) (or MAC PDU) with disabled SL HARQ feedback.SCI1, SCI2, and/or SCI3 may indicate RX UE not to transmit SL HARQfeedback.

For SCI1 in FIG. 8-b, SCI2 in FIG. 9-b, SCI1 in FIG. 9-c, or SCI1 andSCI2 in FIG. 9-d, it may be beneficial to indicate RX UE not to transmitSL HARQ feedback. Since when RX UE may need to select a subset ofderived transmitted SL HARQ feedback(s) or RX UE may need to determinewhether to perform transmission or reception of SL HARQ feedback on aslot with ((pre)configured) PSFCH resources, such SCI indication couldrelease multiple SL HARQ feedbacks collision case of RX UE whendetermining the subset or either the transmission or reception of SLHARQ feedback.

Additionally or alternatively, there may be another embodiment:

Ninth Embodiment

In the ninth embodiment, at least a time gap of any two (adjacent,neighbor, or consecutive) scheduled or assigned sidelink resources maybe less than the minimum time gap Z, and TX UE may generate the TB,which comprises or multiplexes SL data from (only) SL logicalchannel(s)logical channel(s) (or MAC PDU) with enabled SL HARQ feedback.It may mean that the expectation of network node does not align to TXUE's sidelink buffer status.

In one embodiment, the TX UE may (be allowed to) drop, skip, neglect, orcancel specific sidelink resource(s). The TX UE may (be allowed to) notperform sidelink transmission(s) on specific sidelink resource(s). TheTX UE may (be allowed to) not perform sidelink data transmission and/orsidelink control information on the specific sidelink resource(s). TheTX UE may (be allowed to) drop, skip, neglect, or cancel sidelinktransmission(s) on specific sidelink resource(s). The TX UE may (beallowed to) drop, skip, neglect, or cancel sidelink data transmissionand/or sidelink control information on the specific sidelink resource.More specifically, the specific sidelink resource(s) may be scheduled bySL grant from network.

In one embodiment, the specific sidelink resource(s) may be derived ordetermined based on time gap of any two (adjacent, neighbor, orconsecutive) scheduled or assigned sidelink resources. If time gap oftwo (adjacent, neighbor, or consecutive) scheduled or assigned sidelinkresources is larger than or equal to the minimum time gap Z, both thetwo scheduled or assigned sidelink resources may not be the specificsidelink resource(s).

In one embodiment, if time gap of two (adjacent, neighbor, orconsecutive) scheduled or assigned sidelink resources is less than theminimum time gap Z, the first one or the earlier one (in time domain) ofthe two scheduled or assigned sidelink resources may be the specificsidelink resource. The last one (in time domain) or the latter one ofthe two scheduled or assigned sidelink resources may not be the specificsidelink resource(s). Additionally or alternatively, the last one (intime domain) or the latter one of the two scheduled or assigned sidelinkresources may be the specific sidelink resource(s).

Additionally or alternatively, if time gap of two (adjacent, neighbor,or consecutive) scheduled or assigned sidelink resources is less thanthe minimum time gap Z, the last one (in time domain) or the latter oneof the two scheduled or assigned sidelink resources may be the specificsidelink resource. The first one or the earlier one (in time domain) ofthe two scheduled or assigned sidelink resources may not be the specificsidelink resource(s).

In one embodiment, the TX UE may transmit one or more sidelink controlinformation to schedule the one or more sidelink data transmissions. TheTX UE may transmit the one or more sidelink control information toschedule, indicate, or reserve the one or more of the multiple sidelinkresources. The one or more sidelink control information may notschedule, indicate, or reserve the specific sidelink resource(s). The TXUE may transmit the one or more sidelink control information(respectively) on the multiple sidelink resources scheduled or assignedby SL grant, excluding the specific sidelink resources.

In one embodiment, (all) the one or more sidelink control informationmay indicate RX UE to transmit SL HARQ feedback. Furthermore, (all) theone or more sidelink control information may indicate RX UE to transmitSL HARQ feedback, if CBR threshold is not exceed or achieved. It maymean that RX UE may transmit one or more SL HARQ feedback transmissionsassociated with the one or more sidelink data transmission respectively.The RX UE may transmit one or more SL HARQ feedback transmissions on oneor more sidelink feedback resources, which are associated with the oneor more sidelink resources respectively.

As shown in exemplary FIG. 8-b, the time gap of PSSCH1 and PSSCH2 may beless than the minimum time gap Z. The TX UE may perform SCI 1+PSSCH1,and may not perform SCI2+PSSCH2. PSSCH1 may comprise or multiplex SLdata from SL logical channel(s)logical channel(s) (or MAC PDU) withenabled SL HARQ feedback. Additionally or alternatively, TX UE mayperform SCI2+PSSCH2, and may not perform SCI1+PSSCH1. PSSCH2 maycomprise or multiplex SL data from SL logical channel(s)logicalchannel(s) (or MAC PDU) with enabled SL HARQ feedback.

As shown in exemplary FIG. 9-b, the time gap of PSSCH2 and PSSCH3 may beless than the minimum time gap Z. In one embodiment, the TX UE mayperform SCI 1+PSSCH1 and SCI 2+PSSCH2, and may not perform SCI3+PSSCH3.PSSCH1 and PSSCH2 may comprise the same TB, which comprises ormultiplexes SL data from SL logical channel(s) (or MAC PDU) with enabledSL HARQ feedback. Additionally or alternatively, TX UE may performSCI1+PSSCH1 and SCI3+PSSCH3, and may not perform SCI2+PSSCH2. PSSCH1 andPSSCH3 may comprise the same TB, which comprises or multiplexes SL datafrom SL logical channel(s) (or MAC PDU) with enabled SL HARQ feedback.

As shown in exemplary FIG. 9-c, the time gap of PSSCH1 and PSSCH2 may beless than the minimum time gap Z. In one embodiment, the TX UE mayperform SCI1+PSSCH1 and SCI3+PSSCH3, and may not perform SCI2+PSSCH2.PSSCH1 and PSSCH3 may comprise the same TB, which comprises ormultiplexes SL data from SL logical channel(s)logical channel(s) (or MACPDU) with enabled SL HARQ feedback. Additionally or alternatively, theTX UE may perform SCI2+PSSCH2 and SCI3+PSSCH3, and may not performSCI1+PSSCH1. PSSCH2 and PSSCH 3 may comprise the same TB, whichcomprises or multiplexes SL data from SL logical channel(s)logicalchannel(s) (or MAC PDU) with enabled SL HARQ feedback.

As shown in exemplary FIG. 9-d, the time gap of PSSCH1 and PSSCH2 may beless than the minimum time gap Z, and the time gap of PSSCH2 and PSSCH3may be less than the minimum time gap Z. Preferably, the TX UE mayperform SCI 1+PSSCH1 and SCI 3+PSSCH3, and may not perform SCI2+PSSCH2.PSSCH1 and PSSCH3 may comprise the same TB, which comprises ormultiplexes SL data from SL logical channel(s)logical channel(s) (or MACPDU) with enabled SL HARQ feedback. Additionally or alternatively, theTX UE may perform SCI2+PSSCH2, and may not perform SCI1+PSSCH1 or SCI3+PSSCH3. PSSCH2 may comprise or multiplex SL data from SL logicalchannel(s) (or MAC PDU) with enabled SL HARQ feedback.

Method c

The general concept of Method c is that for a first set of logicalchannel(s) or MAC PDU, the minimum time gap Z may not be considered forsidelink resource(s) in mode 1. For a second set of logical channel(s)or MAC PDU, the minimum time gap Z may be considered for sidelinkresource(s) in mode 1.

A TX UE may receive a SL grant from a network node. The SL grant mayschedule or assign multiple sidelink resources. In one embodiment, theTX UE may generate a TB. The TX UE may perform one or more sidelinktransmission(s) on one or more of the multiple sidelink resourcesscheduled or assigned by the SL grant. The one or more sidelinktransmission comprises or delivers the generated TB.

In one embodiment, the TX UE may check whether time gap of any two(adjacent, neighbor, or consecutive) scheduled or assigned sidelinkresources is larger than or equal to the minimum time gap Z.Additionally or alternatively, the TX UE may check whether time gap ofany two (adjacent, neighbor, or consecutive) scheduled or assignedsidelink resources is less than the minimum time gap Z.

In one embodiment, the first set may be (pre-)configured. The second setmay be (pre-)configured. Additionally or alternatively, the first setmay comprise or mean logical channel(s) (or MAC PDU) with disabled SLHARQ feedback. The second set may comprise/mean logical channel(s) (orMAC PDU) with enabled SL HARQ feedback.

Additionally or alternatively, the first set may be (pre-)configuredwith priority lower than a threshold. The second set may be(pre-)configured with priority higher than a threshold. Additionally oralternatively, a first subset of the second set may be utilized if timegap of any two (adjacent, neighbor, or consecutive) scheduled orassigned sidelink resources is larger than or equal to the minimum timegap Z. A second subset of the second set may be utilized if time gap ofany two (adjacent, neighbor, or consecutive) scheduled or assignedsidelink resources is less than the minimum time gap Z. In oneembodiment, the first subset of the second set may be configured withenabled SL HARQ feedback. The second subset of the second set may beconfigured with disabled SL HARQ feedback.

In one embodiment, if (all) time gap of any two (adjacent, neighbor, orconsecutive) scheduled or assigned sidelink resources is larger than orequal to the minimum time gap Z, the TX UE may determine to selectlogical channel(s) (or MAC PDU) among the first set and the second set.The TX UE may generate a TB, which comprises or multiplexes SL data fromlogical channel(s) (or MAC PDU) (only) among the first set and thesecond set. In other word, the LCP for the TB may be performed among(only) the first set and the second set of logical channel(s) (or MACPDU). In one embodiment, the LCP for the TB may be performed among(only) the first set and the second set of logical channel(s) (or MACPDU) and with available SL data and with SBj>0.

In one embodiment, if at least a time gap of any two (adjacent,neighbor, or consecutive) scheduled or assigned sidelink resources isless than the minimum time gap Z, the TX UE may determine to selectlogical channel(s)logical channel(s) (or MAC PDU) among the first set.The TX UE may generate a TB, which comprises or multiplexes SL data fromlogical channel(s) (or MAC PDU) (only) among the first set. The TX UEmay preclude or exclude from selecting the second subset of logicalchannel(s)logical channel(s) (or MAC PDU). The TX UE may generate a TB,which precludes or excludes from comprising or multiplexing SL data fromsecond set of logical channel(s)logical channel(s) (or MAC PDU). Inother words, the LCP for the TB may be performed among (only) the firstset of logical channel(s)logical channel(s) (or MAC PDU). In oneembodiment, the LCP for the TB may be performed among (only) the firstset of logical channel(s) (or MAC PDU) and with available SL data andwith SBj>0.

In one embodiment, if at least a time gap of any two (adjacent,neighbor, or consecutive) scheduled or assigned sidelink resources islarger than or equal to the minimum time gap Z, the TX UE may determineto select logical channel(s)logical channel(s) (or MAC PDU) among thefirst set and the second set. The TX UE may generate a TB, whichcomprises or multiplexes SL data from logical channel(s)logicalchannel(s) (or MAC PDU) (only) among the first set and the second set.In other words, the LCP for the TB may be performed among (only) thefirst set and the second set of logical channel(s)logical channel(s) (orMAC PDU). In one embodiment, the LCP for the TB may be performed among(only) the first set and the second set of logical channel(s)logicalchannel(s) (or MAC PDU) and with available SL data and with SBj>0.

In one embodiment, if (all) time gap of any two (adjacent, neighbor, orconsecutive) scheduled or assigned sidelink resources is less than theminimum time gap Z, the TX UE may determine to select logicalchannel(s)logical channel(s) (or MAC PDU) among the first set. The TX UEmay generate a TB, which comprises or multiplexes SL data from logicalchannel(s) (or MAC PDU) (only) among the first set. The TX UE maypreclude or exclude from selecting the second subset of logicalchannel(s) (or MAC PDU). The TX UE may generate a TB, which precludes orexcludes from comprising or multiplexing SL data from second set oflogical channel(s) (or MAC PDU). In other words, the LCP for the TB maybe performed among (only) the first set of logical channel(s) (or MACPDU). In one embodiment, the LCP for the TB may be performed among(only) the first set of logical channel(s)logical channel(s) (or MACPDU) and with available SL data and with SBj>0.

In one embodiment, if (all) time gap of any two (adjacent, neighbor, orconsecutive) scheduled or assigned sidelink resources is larger than orequal to the minimum time gap Z, the TX UE may determine to selectlogical channel(s)logical channel(s) (or MAC PDU) among the first setand the first subset. The TX UE may generate a TB, which comprises ormultiplexes SL data from logical channel(s) (or MAC PDU) (only) amongthe first set and the first subset. The TX UE may preclude or excludefrom selecting the second subset of logical channel(s)logical channel(s)(or MAC PDU). The TX UE may generate a TB, which precludes or excludesfrom comprising or multiplexing SL data from second set of logicalchannel(s) (or MAC PDU). In other words, the LCP for the TB may beperformed among (only) the first set and the first subset of logicalchannel(s)logical channel(s) (or MAC PDU). In one embodiment, the LCPfor the TB may be performed among (only) the first set and the firstsubset of logical channel(s) (or MAC PDU) and with available SL data andwith SBj>0.

In one embodiment, if at least a time gap of any two (adjacent,neighbor, or consecutive) scheduled or assigned sidelink resources isless than the minimum time gap Z, the TX UE may determine to selectlogical channel(s)logical channel(s) (or MAC PDU) among the first setand the second subset. The TX UE may generate a TB, which comprises ormultiplexes SL data from logical channel(s) (or MAC PDU) (only) amongthe first set and the second subset. The TX UE may preclude or excludefrom selecting the first subset of logical channel(s)logical channel(s)(or MAC PDU). The TX UE may generate a TB, which precludes or excludesfrom comprising or multiplexing SL data from first set of logicalchannel(s)logical channel(s) (or MAC PDU). In other words, the LCP forthe TB may be performed among (only) the first set and the second subsetof logical channel(s)logical channel(s) (or MAC PDU). In one embodiment,the LCP for the TB may be performed among (only) the first set and thesecond subset of logical channel(s) (or MAC PDU) and with available SLdata and with SBj>0.

In one embodiment, if at least a time gap of any two (adjacent,neighbor, or consecutive) scheduled or assigned sidelink resources islarger than or equal to the minimum time gap Z, the TX UE may determineto select logical channel(s)logical channel(s) (or MAC PDU) among thefirst set and the first subset. The TX UE may generate a TB, whichcomprises or multiplexes SL data from logical channel(s) (or MAC PDU)(only) among the first set and the first subset. The TX UE may precludeor exclude from selecting the second subset of logical channel(s) (orMAC PDU). The TX UE may generate a TB, which precludes or excludes fromcomprising or multiplexing SL data from second set of logical channel(s)(or MAC PDU). In other word, the LCP for the TB may be performed among(only) the first set and the first subset of logical channel(s) (or MACPDU). In one embodiment, the LCP for the TB may be performed among(only) the first set and the first subset of logical channel(s) (or MACPDU) and with available SL data and with SBj>0.

In one embodiment, if (all) time gap of any two (adjacent, neighbor, orconsecutive) scheduled or assigned sidelink resources is less than theminimum time gap Z, the TX UE may determine to select logical channel(s)(or MAC PDU) among the first set and the second subset. The TX UE maygenerate a TB, which comprises or multiplexes SL data from logicalchannel(s) (or MAC PDU) (only) among the first set and the secondsubset. The TX UE may preclude or exclude from selecting the firstsubset of logical channel(s) (or MAC PDU). The TX UE may generate a TB,which precludes or excludes from comprising or multiplexing SL data fromfirst set of logical channel(s)logical channel(s) (or MAC PDU). In otherwords, the LCP for the TB may be performed among (only) the first setand the second subset of logical channel(s) (or MAC PDU). In oneembodiment, the LCP for the TB may be performed among (only) the firstset and the second subset of logical channel(s)logical channel(s) (orMAC PDU) and with available SL data and with SBj>0.

For all Above Concepts, Methods, Alternatives and Embodiments

Note that any of above methods, alternatives and embodiments may becombined or applied simultaneously.

In one embodiment, the TX UE may check whether the sidelink resourcesscheduled or assigned by the SL grant can fulfill latency requirement ofthe SL data comprised or multiplexed in the TB. When the TX UE generatesthe TB for sidelink transmission, the TX UE can select (only) thelogical channel(s) or MAC PDU wherein the sidelink resources scheduledor assigned by the SL grant satisfies the latency requirement of thelogical channel(s) or MAC PDU. The TX UE may preclude or exclude toselect the logical channel(s) or MAC PDU wherein the sidelink resourcesscheduled or assigned by the SL grant does not satisfy the latencyrequirement of the logical channel(s) or MAC PDU.

In one embodiment, when the TX UE generates the TB for sidelinktransmission, the TX UE can select (only) the logical channel(s) or MACPDU with latency requirement larger than or equal to the sidelinkresources scheduled or assigned by the SL grant. The TX UE may precludeor exclude selecting the logical channel(s) or MAC PDU with latencyrequirement less than the sidelink resources scheduled or assigned bythe SL grant.

In one embodiment, when the TX UE generates the TB for sidelinktransmission, the TX UE can select (only) the logical channel(s) or MACPDU with latency requirement larger than or equal to time gap betweenthe first one and the last one (in time domain) among the sidelinkresources scheduled or assigned by the SL grant. The TX UE may precludeor exclude selecting the logical channel(s) or MAC PDU with latencyrequirement less than time gap between the first one and the last one(in time domain) among the sidelink resources scheduled or assigned bythe SL grant.

In one embodiment, when the TX UE generates the TB for sidelinktransmission, the TX UE can select (only) the logical channel(s) or MACPDU with latency requirement larger than or equal to the last one (intime domain) of the sidelink resources scheduled or assigned by the SLgrant. The TX UE may preclude or exclude selecting the logicalchannel(s) or MAC PDU with latency requirement less than the last one(in time domain) of the sidelink resources scheduled/assigned by the SLgrant.

In one embodiment, the latency requirement may mean validity time of theSL data. The latency requirement may mean remaining packet delay budget.

In one embodiment, the RX UE may transmit one or more SL HARQ feedbackto the TX UE. The TX UE may receive or detect one or more SL HARQfeedback from the RX UE. The SL HARQ feedback may be associated with theone or more sidelink transmission(s). The SL HARQ feedback may beassociated with the one or more sidelink data transmission(s) and/or theone or more sidelink control information.

In one embodiment, the TX UE may report corresponding HARQ report tonetwork node. The corresponding HARQ report may indicate whether the TXUE requests additional or other sidelink resources for retransmission ofthe TB or not. The corresponding HARQ report may be set based on the oneor more SL HARQ feedback. The corresponding HARQ report may be set basedon SL HARQ feedback associated with the last one of the one or moresidelink transmission(s) (in time domain). The corresponding HARQ reportmay be set based on SL HARQ feedback associated with the last onesidelink resource (in time domain).

In one embodiment, the HARQ report may comprise an HARQ-ACK location.The HARQ-ACK location may correspond to or may deliver SL HARQ feedback,wherein the SL HARQ feedback is associated to the SL grant. The HARQ-ACKlocation may correspond to or may deliver a SL HARQ feedback, whereinthe SL HARQ feedback is set based on the one or more SL HARQ feedback(e.g. set as the last SL HARQ feedback). The HARQ-ACK location maycorrespond to or may deliver a SL HARQ feedback, wherein the SL HARQfeedback is one of the one or more SL HARQ feedback (e.g. the last SLHARQ feedback). The HARQ-ACK location may be determined based on (slotof, time resource of, frequency resource of, and/or code resource of)PSFCH comprising the SL HARQ-ACK. The HARQ-ACK location may bedetermined based on (slot of, time resource of, frequency resource of,and/or code resource of) PSFCH, wherein the PSFCH is associated to thelast or latest scheduled sidelink resource by the SL grant.

For example, in FIG. 9-b, assuming PSFCH1 is associated to PSSCH1,PSFCH2 is associated to PSSCH2, and PSFCH3 is associated to PSSCH3,PSFCH2 and PSFCH 3 may be in a same slot and/or occupy same symboland/or occupy different frequency resources. PSFCH1 may be in differentslot than PSFCH2 and PSFCH3. If TX UE decides to transmit PSSCH1 andPSSCH2, TX UE may consider PSSCH3 is specific sidelink resource and doesnot transmit PSSCH3 (due to time gap smaller than Z compared to PSSCH2).In this example, although there is no PSSCH3 transmission, TX UE maydetermine or place the received SL HARQ feedback from PSFCH2 on aHARQ-ACK location in a HARQ report. The HARQ-ACK location may bedetermined based on or associated to PSFCH3 (rather than PSFCH2). TX UEtransmits the HARQ report on a PUCCH resource, wherein time resource ofthe PUCCH resource is referred to PSFCH3.

In one embodiment, the TX UE may transmit or deliver an information tonetwork node. The information may indicate whether TB comprises ormultiplexes SL data from (only) logical channel(s)logical channel(s) (orMAC PDU) with enabled SL HARQ feedback or SL data from (only) logicalchannel(s)logical channel(s) (or MAC PDU) with disabled SL HARQfeedback. The information may indicate whether the requested additionalor other sidelink resources for retransmission of the TB need to satisfythat time gap of any two (adjacent, neighbor, or consecutive) additionalor another sidelink resources may be larger than or equal to the minimumtime gap Z or not. The information may indicate that the TX UE requestsadditional or other sidelink resources for retransmission of the TB withtime gap of any two (adjacent, neighbor, or consecutive) additional oranother sidelink resources being larger than or equal to the minimumtime gap Z, or to indicate that the TX UE requests additional or othersidelink resources for retransmission of the TB with time gap of any two(adjacent, neighbor, or consecutive) additional or another sidelinkresources being less than the minimum time gap Z. The information mayindicate whether the requested additional or another sidelink resourcesfor retransmission of the TB need to satisfy the minimum time gap Z ornot. The information may indicate that the TX UE requests additional orother sidelink resources for retransmission of the TB with need ofsatisfying the minimum time gap Z, or to indicate that the TX UErequests additional or other sidelink resources for retransmission ofthe TB without need of satisfying the minimum time gap Z. Theinformation may be HARQ-ACK in a location in the HARQ report.

In one embodiment, a combination of locations in the HARQ report couldindicate the SL HARQ-ACK associated to the SL grant and the information.For example, in FIG. 9-b, TX UE transmits PSSCH1 and PSSCH2 and does nottransmit PSSCH3, and TX UE receives SL HARQ-ACK in PSFCH 2. In thisexample, TX UE transmits the SL HARQ-ACK on a location associated toPSFCH3 and places the information in a second location associated toPSFCH2 (for indicating PSSCH2 is not transmitted). When the networkreceives HARQ report, the network may know the situation that the TX UEdoes not transmit PSSCH2 due to some reasons (e.g., does not meetminimum time gap Z requirement). In this example, possible combinationof locations could be (the information or ACK, the SL HARQ-ACK)associated to (PSFCH2, PSFCH3). In general, only one location isassociated to SL HARQ-ACK (the location associated to PSFCH3), and theother locations associated to PSFCH1 and/or PSFCH2 may be reserved ormeaningless.

Hence, in FIG. 9-b, TX UE indicates (NACK, the information or ACK, theSL HARQ-ACK) associated to (PSFCH1, PSFCH2, PSFCH3). If there is anearlier HARQ report associated to another SL grant, and the earlier HARQreport comprises location associated to PSFCH1, TX UE could transmit theinformation on the location in case TX UE does not transmit or decidesnot to transmit PSSCH1 (due to not meet minimum time gap Z requirement).

As another example, in FIG. 9-c, in case TX UE does not transmit PSSCH1,TX UE transmits the information on a location associated to PSFCH1. Incase TX UE does not transmit PSSCH2, TX UE transmits the information ona location associated to PSFCH2. Furthermore, in FIG. 9-d, in case TX UEtransmits PSSCH1 and PSSCH3, TX UE transmits the information on alocation associated to PSFCH2 and/or transmits the received SL HARQ-ACK(on PSFCH1 and/or PSFCH3) on a location associated to PSFCH3.

In one embodiment, TX UE may transmit the information on a locationassociated to PSFCH1. The network may determine whether scheduledsidelink resource(s) associated to SL grant meet the requirement Z ornot based on the information received on any one of location(s)associated to PSFCH corresponding to each scheduled sidelink resource. Alocation may mean a location in a HARQ report to the network.

In one embodiment, the information on a location associated to PSFCH2may indicate that PSSCH1 and PSSCH2 does not meet time gap requirementand/or that PSSCH2 and PSSCH3 does not meet time gap requirement.

In one embodiment, the TX UE may deliver the information with thecorresponding HARQ report. The information may be delivered via a fieldor some bits (e.g. one bit). The information may be delivered via uplinkresource selection, and the corresponding HARQ report is transmitted inthe selected uplink resource. For instance, a first uplink resource maybe for requesting additional or other sidelink resources with a need tosatisfy the minimum time gap Z, and a second uplink resource may be forrequesting additional or other sidelink resources without a need tosatisfy the minimum time gap Z. The TX UE may select either the firstuplink resource or the second uplink resource, based on the information.

In one embodiment, the TX UE may receive another SL grant, whichschedules or assigns another multiple sidelink resources. Preferably,the another SL grant may schedule or assign the additional or othersidelink resources for retransmission of the TB. The another SL grantmay indicate the same HARQ process ID as the SL grant, and/or theanother SL grant may indicate non-toggled or the same NDI value as theSL grant.

In one embodiment, the TX UE may receive the another SL grant before thelast sidelink resources scheduled or assigned by the SL grant (in timedomain). The TX UE may take the another multiple sidelink resources intoconsideration when determining whether or which sidelink controlinformation(s) indicates RX UE to transmit SL HARQ feedback or not.

In one embodiment, the minimum time gap may be (pre-)configured orspecified. The minimum time gap may comprise a time gap ‘a’ and a timegap ‘b’. The time gap ‘a’ may be a time gap between the end of the lastsymbol of the PSSCH transmission of the first resource and the start ofthe first symbol of the corresponding PSFCH reception. The time gap ‘a’may be determined by resource pool configuration and/or higher layerparameters of MinTimeGapPSFCH and/or periodPSFCHresource. The time gap‘a’ may be in unit of sidelink TTI. The time gap ‘a’ may be in unit oflogical TTI. The time gap ‘a’ may be in unit of sidelink slot orsidelink symbol. The time gap ‘a’ may not be in unit of physical TTI ormini-second.

In one embodiment, the time gap ‘b’ may be a time required for PSFCHreception and/or processing plus sidelink retransmission preparation.The time for processing plus sidelink retransmission preparation mayinclude any of multiplexing of necessary physical channels and/or anyTX-RX or RX-TX switching time. The time gap ‘b’ may be determined by UEimplementation. The time gap ‘b’ may be determined by UE capability. Thetime gap ‘b’ may be (pre-)configured or specified.

In one embodiment, the time gap ‘b’ may be in units of physical TTImini-seconds, physical slots or physical symbols, logical TTIs orsidelink TTIs, or sidelink slots. The time gap ‘b’ may not be in unitsof physical TTIs or mini-seconds.

In one embodiment, the minimum time gap utilized in mode 1 may be thesame as the minimum time gap utilized in mode 2. Additionally oralternatively, the minimum time gap utilized in mode 1 may be differentfrom the minimum time gap utilized in mode 2.

In one embodiment, the multiple sidelink resources scheduled or assignedby the SL grant may be in the same sidelink resource pool. Any twosidelink resources of the multiple sidelink resources scheduled orassigned by the SL grant are in different slot. Any two sidelinkresources of the multiple sidelink resources scheduled or assigned bythe SL grant could have the same or different frequency resourceallocation (e.g., occupying same or different location of sub-channels).Any two sidelink resources of the multiple sidelink resources scheduledor assigned by the SL grant could have the same number of sub-channels.

In one embodiment, the higher layer of the first device may mean MAClayer or RRC layer. The sidelink data transmission may be or may meanPSSCH. The sidelink control information may be delivered via PSCCH. Thesidelink control information may mean 1^(st)-stage sidelink controlinformation or 2^(nd)-stage sidelink control information. The sidelinkcontrol information comprises scheduling information of PSSCHtransmission scheduled by the PSCCH.

In one embodiment, a (physical) TTI may comprise multiple symbols, e.g.12 or 14 symbols. The sidelink TTI may be a slot (fully or partially)comprising sidelink symbols. The sidelink TTI may mean a transmissiontime interval for a sidelink (data) transmission.

In one embodiment, a sidelink slot may contain all OFDM symbolsavailable for sidelink transmission in a (physical) TTI. A sidelink slotmay contain a consecutive number symbols available for sidelinktransmission in a (physical) TTI. The symbol may mean a symbolindicated/configured for sidelink.

In one embodiment, a sub-channel is a unit for sidelink resourceallocation or scheduling (for PSSCH). A sub-channel may comprisemultiple contagious PRBs in frequency domain. The number of PRBs foreach sub-channel may be (pre-)configured for a sidelink resource pool. Asidelink resource pool (pre-)configuration may indicate or configure thenumber of PRBs for each sub-channel. The number of PRBs for eachsub-channel may be any of 10, 15, 20, 25, 50, 75, or 100. A sub-channelmay be represented as a unit for sidelink resource allocation orscheduling.

In one embodiment, the SL HARQ feedback may be delivered via PSFCH. ForPSCCH and/or PSSCH transmitted from TX UE to RX UE, the RX UE maytransmit PSFCH for delivering SL HARQ feedback in response of detectingor receiving PSCCH and/or PSSCH. The SL HARQ feedback may comprise ACKor NACK. The SL HARQ feedback for TB may be derived based on whether theRX UE successfully receives or decodes the data packet delivered in theassociated PSSCH transmission. The SL HARQ feedback as DTX may mean theTX UE may not detect or receive the PSFCH transmission or may detectneither ACK nor NACK.

In one embodiment, the HARQ report to network node may be delivered viaPUCCH or PUSCH. The TX UE may transmit PUCCH or PUSCH for delivering theHARQ report to network node. The PUCCH resource may be indicated by theSL grant. The time occasion of the PUCCH resource may be indicated bythe SL grant.

In one embodiment, a TB may mean a sidelink data packet. A sidelink datapacket may mean a MAC PDU. The Destination of the TB may be the RX UE.The Destination of the TB may be associated with unicast sidelinktransmission. The Destination of the TB may be a sidelink group. Thesidelink group may comprise the RX UE and/or the TX UE. The Destinationof the TB may be associated with groupcast sidelink transmission. TheDestination of the TB may be surrounding UE(s). The surrounding UE maycomprise the RX UE. The Destination of the TB may be associated withbroadcast sidelink transmission.

In one embodiment, the sidelink transmission or reception may bedevice-to-device transmission or reception. The sidelink transmission orreception may be V2X (e.g. V2V or V2P or V21) transmission or reception.The sidelink transmission or reception may be P2X (e.g. P2V or P2P orP2I) transmission or reception. The sidelink transmission or receptionmay be on PC5 interface.

In one embodiment, the PC5 interface may be wireless interface forcommunication between device and device. The PC5 interface may bewireless interface for communication between devices. The PC5 interfacemay be wireless interface for communication between UEs. The PC5interface may be wireless interface for V2X or P2X communication. The Uuinterface may be wireless interface for communication between networknode and device. The Uu interface may be wireless interface forcommunication between network node and UE.

In one embodiment, the network node may be a gNB. The network node maybe a base station. The network node may be a RSU. The network node maybe a network-type RSU. The network node may be a UE-type RSU. Thenetwork node may be replaced or represented by a specific device withina sidelink group. The network node may be a scheduling device or leaderdevice within a sidelink group. The network node may be replaced orrepresented by a relay device or a relay UE.

In one embodiment, the TX UE and the RX UE may be different UEs. The TXUE may be a device. In particular, the TX UE may be a vehicle UE, apedestrian UE, or a V2X UE. The TX UE may also be a transmitting device,a network-type RSU, or a UE-type RSU. IN one embodiment, the TX UE maybe a specific device within a sidelink group. The TX UE may be ascheduling device or leader device within a sidelink group. The TX UEmay be a relay device, or a remote device.

In one embodiment, the RX UE may be a device. In particular, the RX UEmay be a vehicle UE, a pedestrian UE, or a V2X UE. The RX UE may be atransmitting device, a network-type RSU, or a UE-type RSU. In oneembodiment, the RX UE may be a specific device within a sidelink group.The RX UE may be a scheduling device or leader device within a sidelinkgroup. The RX UE may be a relay device, or a remote device.

In one embodiment, the HARQ report could be a semi-static or dynamicHARQ codebook. The HARQ report could be type-1 or type-2 HARQ codebook.The semi-static HARQ codebook comprising locations associated to a setof timing (e.g., kl timing between slot containing PSFCH and slotcontaining PUCCH for delivering the HARQ report) and number of PSSCHslot associated to a PSFCH slot. The dynamic HARQ codebook comprisinglocations associated to a set of timing (e.g., kl timing between slotcontaining PSFCH and slot containing PUCCH for delivering the HARQreport), number of PSSCH slot associated to a PSFCH slot, and/ormonitoring occasion(s) for SL grant.

FIG. 10 is a flow chart 1000 according to one exemplary embodiment fromthe perspective of a device to perform sidelink communication. In step1005, the device receives a sidelink grant from a network node, whereinthe sidelink grant schedules or assigns multiple sidelink resources. Instep 1010, the device generates a data packet comprising or multiplexingsidelink data from SL logical channel(s) with SL HARQ feedback enabled.In step 1015, the device performs two sidelink transmissions for thedata packet on two adjacent, neighbor, or consecutive sidelink resourcesamong the multiple sidelink resources if a time gap of the two adjacent,neighbor, or consecutive sidelink resources is larger than or equal to aminimum time gap. In step 1020, the device is allowed to drop, skip, orcancel a sidelink transmission on one sidelink resource of the twoadjacent, neighbor, or consecutive sidelink resources among the multiplesidelink resources if the time gap of the two adjacent, neighbor, orconsecutive sidelink resources is less than a minimum time gap.

In one embodiment, the device could perform one or more sidelinktransmission(s) for the data packet on the multiple sidelink resources,excluding the one sidelink resource if the time gap of the two adjacent,neighbor, or consecutive sidelink resources is less than a minimum timegap. In one embodiment, the device could perform sidelink transmissionfor the data packet on each of the multiple sidelink resources,excluding the one sidelink resource if the time gap of the two adjacent,neighbor, or consecutive sidelink resources is less than a minimum timegap.

In one embodiment, the device is allowed to drop, skip, or cancel thesidelink transmission on the one sidelink resource could mean orcomprise that the device determines to perform or to drop, skip orcancel the sidelink transmission on the one sidelink resource if thetime gap of the two adjacent, neighbor, or consecutive sidelinkresources is less than a minimum time gap. Furthermore, the device isallowed to drop, skip, or cancel the sidelink transmission on the onesidelink resource could mean or comprise that the device determineswhether to drop, skip, or cancel the sidelink transmission on the onesidelink resource if the time gap of the two adjacent, neighbor, orconsecutive sidelink resources is less than a minimum time gap.

In one embodiment, the one sidelink resource could be the first one orthe earlier one of the two adjacent, neighbor, or consecutive sidelinkresources. The one sidelink resource could be the last one or the latterone of the two adjacent, neighbor, or consecutive sidelink resources.

In one embodiment, the device drops, skips, or cancels the sidelinktransmission on one sidelink resource could mean or comprise that thedevice does not perform the sidelink transmission on the one sidelinkresource.

In one embodiment, when the device generates the data packet, the devicemay not consider or check time gap of any two adjacent, neighbor, orconsecutive sidelink resources among the multiple sidelink resourcesbeing larger or less than a minimum time gap. Furthermore, when thedevice determines or selects logical channel(s) for generating the datapacket, the device may not consider or check time gap of any twoadjacent, neighbor, or consecutive sidelink resources among the multiplesidelink resources being larger or less than a minimum time gap.

In one embodiment, the minimum time gap may comprise a first time gapand a second time gap. Furthermore, the first time gap is between end ofthe last symbol of a Physical Sidelink Shared Channel (PSSCH)transmission and start of the first symbol of corresponding PhysicalSidelink Feedback Channel (PSFCH) reception. In addition, the secondtime gap comprises a time required for PSFCH reception and/or processingplus sidelink retransmission preparation.

Referring back to FIGS. 3 and 4, in one exemplary embodiment of acommunication device to perform sidelink communication. Thecommunication device 300 includes a program code 312 stored in thememory 310. The CPU 308 could execute program code 312 to enable thecommunication device (i) to receive a sidelink grant from a networknode, wherein the sidelink grant schedules or assigns multiple sidelinkresources, (ii) to generate a data packet comprising or multiplexingsidelink data from SL logical channel(s) with SL HARQ feedback enabled,(iii) to perform two sidelink transmissions for the data packet on twoadjacent, neighbor, or consecutive sidelink resources among the multiplesidelink resources if a time gap of the two adjacent, neighbor, orconsecutive sidelink resources is larger than or equal to a minimum timegap, and (iv) to allow (the communication device) to drop, skip, orcancel a sidelink transmission on one sidelink resource of the twoadjacent, neighbor, or consecutive sidelink resources among the multiplesidelink resources if the time gap of the two adjacent, neighbor, orconsecutive sidelink resources is less than a minimum time gap.Furthermore, the CPU 308 can execute the program code 312 to perform allof the above-described actions and steps or others described herein.

FIG. 11 is a flow chart 1100 according to one exemplary embodiment fromthe perspective of a device to perform sidelink communication. In step1105, the device receives a sidelink grant from a network node, whereinthe sidelink grant schedules or assigns multiple sidelink resources. Instep 1110, the device generates a data packet comprising or multiplexingsidelink data from one or more SL logical channel(s), wherein the one ormore SL logical channel(s) is determined or selected at least based ontime gap of any two adjacent sidelink resources among the multiplesidelink resources. In step 1115, the device performs one or moresidelink transmission(s) on one or more of the multiple sidelinkresources, wherein the one or more sidelink transmission(s) delivers orcomprises the data packet.

In one embodiment, when (at least) a time gap of any two adjacent,neighbor, or consecutive sidelink resources among the multiple sidelinkresources is less than a minimum time gap, the device could determine toselect (only) SL logical channel(s) with SL HARQ feedback disabled.Furthermore, when (all) the time gap of any two adjacent, neighbor, orconsecutive sidelink resources among the multiple sidelink resources islarger than or equal to a minimum time gap, the device could be allowedto select SL logical channel(s) with SL HARQ feedback enabled.

In one embodiment, the minimum time gap may comprise a first time gapand a second time gap. The first time gap may be between end of the lastsymbol of a PSSCH transmission and start of the first symbol ofcorresponding PSFCH reception. The second time gap may comprise a timerequired for PSFCH reception and/or processing plus sidelinkretransmission preparation.

Referring back to FIGS. 3 and 4, in one exemplary embodiment of acommunication device to perform sidelink communication. Thecommunication device 300 includes a program code 312 stored in thememory 310. The CPU 308 could execute program code 312 to enable thecommunication device (i) to receive a sidelink grant from a networknode, wherein the sidelink grant schedules or assigns multiple sidelinkresource, (ii) to generate a data packet comprising or multiplexingsidelink data from one or more SL logical channel(s), wherein the one ormore SL logical channel(s) is determined or selected at least based ontime gap of any two adjacent sidelink resources among the multiplesidelink resources, and (iii) to perform one or more sidelinktransmission(s) on one or more of the multiple sidelink resources,wherein the one or more sidelink transmission(s) delivers or comprisesthe data packet. Furthermore, the CPU 308 can execute the program code312 to perform all of the above-described actions and steps or othersdescribed herein.

Various aspects of the disclosure have been described above. It shouldbe apparent that the teachings herein may be embodied in a wide varietyof forms and that any specific structure, function, or both beingdisclosed herein is merely representative. Based on the teachings hereinone skilled in the art should appreciate that an aspect disclosed hereinmay be implemented independently of any other aspects and that two ormore of these aspects may be combined in various ways. For example, anapparatus may be implemented or a method may be practiced using anynumber of the aspects set forth herein. In addition, such an apparatusmay be implemented or such a method may be practiced using otherstructure, functionality, or structure and functionality in addition toor other than one or more of the aspects set forth herein. As an exampleof some of the above concepts, in some aspects concurrent channels maybe established based on pulse repetition frequencies. In some aspectsconcurrent channels may be established based on pulse position oroffsets. In some aspects concurrent channels may be established based ontime hopping sequences. In some aspects concurrent channels may beestablished based on pulse repetition frequencies, pulse positions oroffsets, and time hopping sequences.

Those of skill in the art would understand that information and signalsmay be represented using any of a variety of different technologies andtechniques. For example, data, instructions, commands, information,signals, bits, symbols, and chips that may be referenced throughout theabove description may be represented by voltages, currents,electromagnetic waves, magnetic fields or particles, optical fields orparticles, or any combination thereof.

Those of skill would further appreciate that the various illustrativelogical blocks, modules, processors, means, circuits, and algorithmsteps described in connection with the aspects disclosed herein may beimplemented as electronic hardware (e.g., a digital implementation, ananalog implementation, or a combination of the two, which may bedesigned using source coding or some other technique), various forms ofprogram or design code incorporating instructions (which may be referredto herein, for convenience, as “software” or a “software module”), orcombinations of both. To clearly illustrate this interchangeability ofhardware and software, various illustrative components, blocks, modules,circuits, and steps have been described above generally in terms oftheir functionality. Whether such functionality is implemented ashardware or software depends upon the particular application and designconstraints imposed on the overall system. Skilled artisans mayimplement the described functionality in varying ways for eachparticular application, but such implementation decisions should not beinterpreted as causing a departure from the scope of the presentdisclosure.

In addition, the various illustrative logical blocks, modules, andcircuits described in connection with the aspects disclosed herein maybe implemented within or performed by an integrated circuit (“IC”), anaccess terminal, or an access point. The IC may comprise a generalpurpose processor, a digital signal processor (DSP), an applicationspecific integrated circuit (ASIC), a field programmable gate array(FPGA) or other programmable logic device, discrete gate or transistorlogic, discrete hardware components, electrical components, opticalcomponents, mechanical components, or any combination thereof designedto perform the functions described herein, and may execute codes orinstructions that reside within the IC, outside of the IC, or both. Ageneral purpose processor may be a microprocessor, but in thealternative, the processor may be any conventional processor,controller, microcontroller, or state machine. A processor may also beimplemented as a combination of computing devices, e.g., a combinationof a DSP and a microprocessor, a plurality of microprocessors, one ormore microprocessors in conjunction with a DSP core, or any other suchconfiguration.

It is understood that any specific order or hierarchy of steps in anydisclosed process is an example of a sample approach. Based upon designpreferences, it is understood that the specific order or hierarchy ofsteps in the processes may be rearranged while remaining within thescope of the present disclosure. The accompanying method claims presentelements of the various steps in a sample order, and are not meant to belimited to the specific order or hierarchy presented.

The steps of a method or algorithm described in connection with theaspects disclosed herein may be embodied directly in hardware, in asoftware module executed by a processor, or in a combination of the two.A software module (e.g., including executable instructions and relateddata) and other data may reside in a data memory such as RAM memory,flash memory, ROM memory, EPROM memory, EEPROM memory, registers, a harddisk, a removable disk, a CD-ROM, or any other form of computer-readablestorage medium known in the art. A sample storage medium may be coupledto a machine such as, for example, a computer/processor (which may bereferred to herein, for convenience, as a “processor”) such theprocessor can read information (e.g., code) from and write informationto the storage medium. A sample storage medium may be integral to theprocessor. The processor and the storage medium may reside in an ASIC.The ASIC may reside in user equipment. In the alternative, the processorand the storage medium may reside as discrete components in userequipment. Moreover, in some aspects any suitable computer-programproduct may comprise a computer-readable medium comprising codesrelating to one or more of the aspects of the disclosure. In someaspects a computer program product may comprise packaging materials.

While the invention has been described in connection with variousaspects, it will be understood that the invention is capable of furthermodifications. This application is intended to cover any variations,uses or adaptation of the invention following, in general, theprinciples of the invention, and including such departures from thepresent disclosure as come within the known and customary practicewithin the art to which the invention pertains.

The invention claimed is:
 1. A method of a device to perform sidelinkcommunication, comprising: the device receives a sidelink grant from anetwork node, wherein the sidelink grant schedules or assigns multiplesidelink resources; the device generates a data packet comprising ormultiplexing sidelink data from Sidelink (SL) logical channel(s) with SLHybrid Automatic Request (HARQ) feedback enabled; the device performstwo sidelink transmissions for the data packet on two adjacent orconsecutive sidelink resources among the multiple sidelink resourceswhen a time gap of the two adjacent or consecutive sidelink resources islarger than or equal to a minimum time gap; and the device is allowed todrop, skip, or cancel a sidelink transmission on one sidelink resourceof the two adjacent or consecutive sidelink resources among the multiplesidelink resources when the time gap of the two adjacent or consecutivesidelink resources is less than the minimum time gap.
 2. The method ofclaim 1, wherein the device performs one or more sidelinktransmission(s) for the data packet on the multiple sidelink resources,excluding the one sidelink resource when the time gap of the twoadjacent or consecutive sidelink resources is less than the minimum timegap.
 3. The method of claim 1, wherein the device is allowed to drop,skip, or cancel the sidelink transmission on the one sidelink resourcemeans or comprises that the device determines to perform or to drop,skip or cancel the sidelink transmission on the one sidelink resourcewhen the time gap of the two adjacent or consecutive sidelink resourcesis less than the minimum time gap.
 4. The method of claim 1, wherein thedevice is allowed to drop, skip, or cancel the sidelink transmission onthe one sidelink resource means or comprises that the device determinesto drop, skip, or cancel the sidelink transmission on the one sidelinkresource when the time gap of the two adjacent or consecutive sidelinkresources is less than the minimum time gap.
 5. The method of claim 1,wherein the one sidelink resource is an earlier one of the two adjacentor consecutive sidelink resources.
 6. The method of claim 1, wherein theone sidelink resource is a latter one of the two adjacent or consecutivesidelink resources.
 7. The method of claim 1, wherein the device drops,skips, or cancels the sidelink transmission on one sidelink resourcemeans or comprises that the device does not perform the sidelinktransmission on the one sidelink resource.
 8. The method of claim 1,further comprising: when the device generates the data packet, thedevice does not consider or check time gap of any two adjacent orconsecutive sidelink resources among the multiple sidelink resourcesbeing larger or less than the minimum time gap, and/or when the devicedetermines or selects logical channel(s) for generating the data packet,the device does not consider or check time gap of any two adjacent orconsecutive sidelink resources among the multiple sidelink resourcesbeing larger or less than the minimum time gap.
 9. The method of claim1, wherein the minimum time gap comprises a first time gap and a secondtime gap, wherein the first time gap is between end of a last symbol ofa Physical Sidelink Shared Channel (PSSCH) transmission and start of afirst symbol of corresponding Physical Sidelink Feedback Channel (PSFCH)reception, and wherein the second time gap comprises a time required forPSFCH reception and/or processing plus sidelink retransmissionpreparation.
 10. A method of a device to perform sidelink communication,comprising: the device receives a sidelink grant from a network node,wherein the sidelink grant schedules or assigns multiple sidelinkresources; the device generates a data packet comprising or multiplexingsidelink data from one or more Sidelink (SL) logical channel(s), whereinthe one or more SL logical channel(s) is determined or selected at leastbased on time gap of any two adjacent sidelink resources among themultiple sidelink resources; and the device performs one or moresidelink transmission(s) on one or more of the multiple sidelinkresources, wherein the one or more sidelink transmission(s) delivers orcomprises the data packet.
 11. The method of claim 10, furthercomprising: when (at least) a time gap of any two adjacent orconsecutive sidelink resources among the multiple sidelink resources isless than a minimum time gap, the device determines to select (only) SLlogical channel(s) with SL Hybrid Automatic Request (HARQ) feedbackdisabled.
 12. The method of claim 10, further comprising: when (all) thetime gap of any two adjacent or consecutive sidelink resources among themultiple sidelink resources is larger than or equal to a minimum timegap, the device is allowed to select SL logical channel(s) with SL HARQfeedback enabled.
 13. The method of claim 10, wherein the minimum timegap comprises a first time gap and a second time gap, wherein the firsttime gap is between end of a last symbol of a Physical Sidelink SharedChannel (PSSCH) transmission and start of a first symbol ofcorresponding Physical Sidelink Feedback Channel (PSFCH) reception, andwherein the second time gap comprises a time required for PSFCHreception and/or processing plus sidelink retransmission preparation.14. A communication device, comprising: a control circuit; a processorinstalled in the control circuit; and a memory installed in the controlcircuit and operatively coupled to the processor; wherein the processoris configured to execute a program code stored in the memory to: receivea sidelink grant from a network node, wherein the sidelink grantschedules or assigns multiple sidelink resources; generate a data packetcomprising or multiplexing sidelink data from Sidelink (SL) logicalchannel(s) with SL Hybrid Automatic Request (HARQ) feedback enabled;perform two sidelink transmissions for the data packet on two adjacentor consecutive sidelink resources among the multiple sidelink resourceswhen a time gap of the two adjacent or consecutive sidelink resources islarger than or equal to a minimum time gap; and allow the communicationdevice to drop, skip, or cancel a sidelink transmission on one sidelinkresource of the two adjacent or consecutive sidelink resources among themultiple sidelink resources when the time gap of the two adjacent orconsecutive sidelink resources is less than the minimum time gap. 15.The communication device of claim 14, wherein the processor isconfigured to execute a program code stored in the memory to: performone or more sidelink transmission(s) for the data packet on the multiplesidelink resources, excluding the one sidelink resource when the timegap of the two adjacent or consecutive sidelink resources is less thanthe minimum time gap.
 16. The communication device of claim 14, whereinallowing the communication device to drop, skip, or cancel the sidelinktransmission on the one sidelink resource means or comprises that thecommunication device determines to perform or to drop, skip or cancelthe sidelink transmission on the one sidelink resource when the time gapof the two adjacent or consecutive sidelink resources is less than aminimum time gap, and/or wherein allowing the communication device todrop, skip, or cancel the sidelink transmission on the one sidelinkresource means or comprises that the communication device determines todrop, skip, or cancel the sidelink transmission on the one sidelinkresource when the time gap of the two adjacent or consecutive sidelinkresources is less than the minimum time gap.
 17. The communicationdevice of claim 14, wherein the one sidelink resource is an earlier oneof the two adjacent or consecutive sidelink resources, or wherein theone sidelink resource is a latter one of the two adjacent or consecutivesidelink resources.
 18. The communication device of claim 14, whereinthe device drops, skips, or cancels the sidelink transmission on onesidelink resource means or comprises that the device does not performthe sidelink transmission on the one sidelink resource.
 19. Thecommunication device of claim 14, wherein the processor is configured toexecute a program code stored in the memory to: not consider or checktime gap of any two adjacent or consecutive sidelink resources among themultiple sidelink resources being larger or less than the minimum timegap when the communication device generates the data packet, and/or notconsider or check time gap of any two adjacent or consecutive sidelinkresources among the multiple sidelink resources being larger or lessthan the minimum time gap when the communication device determines orselects logical channel(s) for generating the data packet.
 20. Thecommunication device of claim 14, wherein the minimum time gap comprisesa first time gap and a second time gap, wherein the first time gap isbetween end of a last symbol of a Physical Sidelink Shared Channel(PSSCH) transmission and start of a first symbol of correspondingPhysical Sidelink Feedback Channel (PSFCH) reception, and wherein thesecond time gap comprises a time required for PSFCH reception and/orprocessing plus sidelink retransmission preparation.